Sexy Japanese Dictionary

愛嘗め ainame "love lick" - otherwise known as "sixty nine" in other countries - the sexual act in which two people give oral sex to each other simultaneously. Otherwise known as "shikusu nain"(six nine) - a position which looks great aesthetically, but in practice there is always problems when the participants are of different heights and generally results in distraction of both from each other's pleasure. I believe the French originally came up with it.
赤ちゃんプレ aka-chan-pure (lit) " Baby play" An act fairly popular amongst businessmen in Japan where they gain pleasure from being treated as a baby with diapers, spankings and the like. See also [Omoraishi pure] Yet another "high ranking businessman with power secretly yearns to be submissive in order to relax" kind of fetish
アナル anaru "Anal" - referring to any kind of anal sex or anal insertion. The word for "ass" is "oshiri"
アナル攻め anaru-zeme (lit) "Anus attack" To play or stimulate the anus with fingers or tongue or in S&M play - to abuse the anal area with various instruments. Use your imagination.
足フェチ ashi-fechi "Foot fetish" Men who like feet, smelly socks and shoes and the licking and worshipping of same. Intimately linked with [ashikoki]. Also carries a definite submissive aspect.
足扱き ashikoki "Footjob" - the act of stimulating the recipient with feet. Usually refers to a male recipient, though one could envisage it being used on females as well. Feet are often covered in tights, stockings or the legendary [Loose socks]. The pleasure is said to also be derived from the submissive aspect of the act.
AV AV "Adult Video" - An "AV-idoru" is an pornstar (One who stars in adult videos). Talk about your euphemisms...

バアチャルデート baacharu deeto "Virtual date" A bit like the virtual pornography videos common in the US, in a virtual date, a video shot from the viewpoint of the client goes on a date with the girl of choice, probably ending up in a bedroom or hotel of some variety. Not entirely unlike an [erogame].
バイブ baibu "vibe" - actually refers to all dildos - but is taken directly from the English for vibrator. However, since nearly all the penis substitutes in Japan are motorized in some way, "vibe" has come to mean dildo. Also called "dendou kokeshui"(specifically referring to vibrators)
爆乳 bakunyuu (lit) " exploding breasts" Large breasts of a proportion only acheivable through cosmetic surgery in human terms, or naturally in doujinshi. See also [kyonyuu] and [chounyuu]. A similar word for this degree of breast size is "dekanyuu" (lit. "huge breasts")
BE BE "Breast Expansion" Intimately associated with [bakunyuu]. Refers to girls of modest proportions suddenly finding themselves in possession of more sizeable (and most of the time, impossible) assets. Useful, since they often go back afterwards, allowing the advantages of having a prodigious bust without the consequences of backache, shoulder pain and not being able to get nice dresses to fit without looking like a slut. See also [kakuchou]

母乳
bonyuu (lit) " mother's milk / lactation" see also [BE] and [bakunyuu]. Fetish involving girls with large breasts who lactate. If in anime/doujinshi usually not in the puerperium (after given birth) - other reasons are given for their lactation, usually spurious. And (paradoxically), the milk comes out when they are amorous, rather when someone is suckling.
打っ掛け bukkake

From the onomatopoeia "splash"- actually not a dirty word but has come to mean a variety of things.
- To ejaculate on your partner's face or body
- An [AV] in which men take turns ejaculating on one woman.
In Western pornography culture, it has inevitably come to mean the latter, as whenever people think of Japanese pornography, they immediately go for the most extreme meaning of a phrase rather than the actual. In manga, both can be achieved at once, due to the fictionally voluminous amount of ejaculate. The equivalent of the equally humerous latex penis porn of the American variety.
ブロケンドルズ buroken doruzu

"Broken Dolls" A fetish fairly reminiscent of Rei Ayanami in Neon Genesis Evangelion. i.e. involving young girls in bandages, casts, medical equipment and various other paraphenalia. Oh, did I mention that they had to be naked? Originated from Frenchman Romain Slocombe who "has an obsession with accidents" in his words. see also [iryou-fetchi]
ブルセラ burusera from "Buruma"(bloomers) and "Sera-fuku"(sailor uniform), referring to the two major uniforms worn by female schoolgirls. Apparently, men will collect and swap these items of clothing which only have value if they have been worn by an actual school-girl.

痴漢行為 chikankoui "Public Groping" The act seen fairly commonly in manga and anime in which women or schoolgirls on a crowded public train in the mornings are felt up by dirty old businessmen who aren't getting any at home. Comes from the words "chikan" (pervert) and "koui" (deed).
チンチン chinchin "penis" - otherwise known as chinko, chimpo, chimpoko and various other variations on a theme. Don't confuse with "chichi" (breasts).
ちんぐりがえし chinguri gaeshi To give a blowjob while being held upside down by the legs (from what I can gather...)
産卵 chinran "Egg laying" A purely doujinshi and hentai fetish involving usually first the impregnation of the victim girl by a monster or alien of some variety, then a brief incubation period before she lays the monsters offspring. Fairly bizarre and not entirely dissociated with [ninpu] (pregnant)
超乳 chounyuu (lit) " Ultra-breasts" Breasts whose size is at the limits of human imagination - definitely not possible without extreme cosmetic surgery in the real world, or just not possible altogether. Often the result of [BE]. Always natural (of course) and held up impossibly by skimpy swimsuits. Often lactate, just through the virtue of being large. (see [bonyuu])
コスプレ cosplay "Costume play" commonly non-sexual, the dressing up of girls in certain outfits - e.g. serafuku (school uniform), miko uniform, nurse uniform, nekomimi (cat ears) etc. Obviously also used in hentai.

デブ / デブセン
debu/debusen Men who like fat women. I can't really imagine the attraction of this particular fetish, but I assume that it's just "one of those things" Presumably gain sexual pleasure from being squeezed between folds of body fat and tummy cleavage. see also [ganmen kijou]
デイープキス diipu kisu lit. "deep kiss". Japanese word for "French kiss" (kiss with tongues).

エッチ ecchi Comes from a Japanese pronounciation of the first two letters of the English spelling of "Hentai" (i.e. H-E) (wasei eigo is the name of this type of word). Usually used as a short form for hentai, or can mean "perverted" or "sex"(as in "ecchi o suru"). When referring to adult material usually tends to mean material which is not perverted enough to be true hentai (softcore pornography)
援助交際 enjo-kosai "compensated dating" a common Japanese euphemism for the process in which fat old businessmen will "hire" high school girls for company, dates and ultimately, sex, in exchange for monetary rewards and expensive things. Otherwise known as "teenage prostitution", or "illegal". Interesting to note that this service is generally run by said schoolgirls and not by some shady backstreet pimps. Only in Japan, eh...

フェチ fechi "fetish" directly from the English
フェラチオ fellatio From the English fellatio (in turn from the Latin) meaning to give a man oral sex. Often abbreviated to "fera" (フェラ） or "fuefuki", it is also referred to as "shakuhachi" (尺八) - the name of an old Japanese instrument (end-blown flute)
褌 fundoshi

As in the underwear worn by sumo wrestlers consisting of a wound cloth g-string type underwear with a rectangular sheet of cloth covering the front. Refers to pornography with girls wearing said underwear and writhing around in a probably very erotic fashion to people who like sumo. And girls. These loincloth type things are apparently occasionally worn at festivals (under yukata, presumably) and suffer the terrible consequence of being easily displaced; not to mention the camel-toe wedgie effect... Not to be confused with the sumo wrestling loincloth (mawashi).
糞尿 funnyou "scatology". Also known as "skatto"(スカット） from the English word. Refers to any sexual play involving faeces, also including enemas [kanchou] and inflation/distention. The faeces is often more voluminous than physically possible on a Western diet (perhaps so for leaf eating South American natives).
ファリー furry "furry" A genre of animated/drawn hentai in which sex involves anthropomorphic animal like creatures based on one of any number of real or mythical animals (for example, dogs, cats, tigers, dragons). Such furries have human characteristics in that usually they are capable of speech and undertake human like lifestyles, but importantly, they still have animal instincts and the resulting sex-scenes are more animalistic in nature, from which the genre draws some of its thrill. A large furry (over 50m) is sometimes referred to as a "macrofurry" (マクロファリー）
二形、ふたなり futanari "double-form" Hermaphrodites. Strictly refers to characters with both sets of genitalia (penis and vagina) and breasts. This is usually achieved either by freak of nature or by a potion/pill/magic spell of some variety. Girls with male genitalia but lacking vaginas are also referred to as futanari, but are usually categorised under [shemale] or[newhalf]. Boys with vaginas are very rare in hentai.
風俗 fuuzoku "culture". Used to refer to Japan's "sexual culture", i.e. soaplands (bath based brothels), image clubs (themed brothels) and pink salons (brothels specialising in oral sex) amongst many others. Also 風俗営業 (fuuzoku eigyo) - "sex industry".

我慢顔 gaman kao "patience face" - Face pornography in which only the woman's face can be seen during sex (commonly as it is sticking through a wall and the rest of the body and the man is obscured) so that the filming focusses on the sexual expressions as she is shafted from behind. Niche pornography.
がんき ganki The act of a woman sitting on a man's face as he gives her cunnilingus and the woman pressing down whilst this occurs. A popular service in Japanese soaplands.
顔面攻撃 ganmen kougeki (lit) "face attack" A variation on S and M play in which the captive girl's face is contorted to make it look ugly so she is embarassed and feels dominated and the men feel domineering and virile. Commonly used are fingers in nostrils or mouth, or retractor devices that hold the mouth or nostrils open attached to a headpiece or collar.
顔射 gansha To ejaculate on your partner's face. A synonym for [bukkake]. Also see [own goal]
ゴックン gokkun onomatopoeia for the sound of swallowing. Specifically refers to the act of ejaculating into the mouth and the swallowing of said semen. There may or may not be a degree of play with the semen before swallowing, and there may be any number of rounds of semen swallowed. Girls who do this are called "gokkun girls" (ゴックンガルズ）
ゴム gomu "gum" - Condom.

強姦
goukan "rape" - non-consensual sexual acts - the staple of Japanese pornography. Unlike Western porn where the female generally dominates the male, making him orgasm without losing control herself, in Japan it seems to be generally considered that a girl shouting "Iya! Konai de!" (No! Don't come near!) is actually saying "Yes! Do me now!" and that this avoidance play is part of the whole sexual act. believe what you like.
グラビア・アイドル gravure idol from "photogravure" (a kind of printing press) and "idol" (the Japanese term referring to a famous young girl in the media), gravure idols are young female models who pose in skimpy swimsuit spreads for glossy magazines aimed at young men. Basically softcore pornography for the teenage populace.

グロ
guro "gore" directly from the English. Extreme violence involving the shedding of blood. May involve dismemberment, disembowelment and snuff (death) themes . Also includes more specific fetishes such as body remodeling [nikutaikaizou], [suitcase girl] or medical fetish [iryou fetchi]

歯大好き ha-daisuki "tooth love" A rather unique Japanese fetish about teeth - the brushing, flossing and rinsing of same, generally without associated nudity or sexual acts. I would guess that the pleasure comes partly from a strange love of teeth and partly from voyeurism.
裸 hadaka (lit) " nude" Actually refers to a brand of erotic softcore pornography in which idols perform various everyday tasks such as housework, cooking, going out to the shops etc. in only one item of clothing (e.g. socks, tie, ribbon). Origin of the famous "naked apron" (ネケドエプロン）

変身
henshin "transformation" refers generally to any transformation (most commonly that of magical girls in anime), but in a hentai context refers to gender transformations in which the subject changes gender due to magic or dodgy science; usually with hilarious (and erotic) consequences. Note that transformation is actual, as opposed to [josou]
変態 hentai "perverted" (well, it wouldn't be complete without this!) Basically refers to anything abnormal or perverted, including people (as in referring to perverts). Outside Japan generally used to refer to animated and drawn anime style pornography.

非エロ
hi-ero "Non-erotic". For example, doujinshi (fan comics) that have no sex or nudity. Paradoxically, they must be labelled "non-ero" since the default state of doujinshi is various types of filth and so the wholesome material must be indicated so as not to disappoint the otaku punters.

貧乳
hinyuu "small chest" Girls with small breasts (AA-A cup size). Does not refer to lolis who have no breasts at all. Equivalent to Western "flat-chested". Commonly used as older small girls with small breasts satisfy the [loli] urges of the otaku populace whilst being legal.
人ずま hitozuma "someone (else)'s wife" pornography involving sex with married women by men who are not their husbands. Obviously, the thrill is in the adultery, but can also involve [shotacon]
本番 honban (lit) "real thing" Real life meaning refers to the movie or sports industry in which it means "one take" or "crucial game", but has become a euphemism for sex, especially in brothels or other shady night places.

放尿
hounyou "urine" Kown in the West as "watersports", "pissplay" and "golden showers" refers to sexual acts revolving around urination. Acts involve the drinking of said urine, bathing in said urine, and the squirting of said urine into various orifices which, suffice to say, it doesn't belong. There are two types in pornography: "gamen hounyou" (我慢放尿) or face urination (self explanatory) and yagai hounyou (野外放尿) or open air urination involving videos of girls urinating in public places. The act of watching a girl urinate is hounyou kansatsu (放尿観察 )

イメクラ imekura short for "image club" A themed brothel in which the prostitutes therein dress up in various uniforms and perform set scenes depending on customer desire. For example, school girl (joshikousei) with the traditional sailor uniforms (serafuku) or catgirls, nurses or any number of different scenarios.

陰核肥大
inkakuhidai "clitoris enlargement" (Fictional) hentai involving girls whose clitoris enlarges to the point of being like a penis and then the use as such. Similar in fetish terms to [futanari], but without any gender transformation. Enlargement may be achieved by injections or pills. The enlarged clitoris itself may take on the characteristics of an actual penis or remain smooth and bulletlike, depending on the artist's discretion. Either way, it's much hotter than strap-on dildos.
陰茎肥大 inkeihidai "penis expansion" (fictional) hentai in which the man's penis is small but by magic, science or otherwise suddenly becomes large and virile, which is then used on girls to greater effect than before and much heavy moaning. If only things were so simple in real life...
医療フェチ iryou fechi "medical fetish". Fetish revolving around medical play. Encompasses many other fetishes including nurses' uniforms, measurement fetish [keisoku fechi], broken dolls fetish, gynaecological exam fetish [kusuko fechi], enemas [kanchou] etc. Hopefully doesn't extend into guro, but you never know. The thrill seems to come from the extremely submissive role of the patient in a medical setting and the thrill of hot doctors/fit nurses examining you and erring into malpractice. If only life was so simple...

直飲み jikanomi "direct drinking" To drink the urine directly from a girl's genitalia by direct contact. Another soapland practice.
女王様 joousama (lit) "queen" refers to a Dominatrix - i.e. a woman who dominates in S & M play.
女郎 jorou "prostitute" - Girl sold into prostitution. Also known as "panpan" (ぱんぱん), "abazure" (阿婆擦れ), "yotaka" (夜鷹) - Nightjar or also referring to night time soba vendors!
女装 josou "wearing female clothing" cross dressing or transvestitism. Refers to pornography in which people dress up as the opposite sex (usually men dressing as women). Commonly known as "trap" thanks to 4chan.org, "josou" is often mistaken for [shemale] or [newhalf] in hentai. Needless to say that transvestitism works a lot better in drawn hentai as opposed to live action movies.
熟女 jukujo "attractive middle aged lady" Commonly known as MILF.

獣姦
juukan "bestiality" sex with animals, which exists in Japanese pornography as it does in underground Western fare. Of course, in animated and drawn hentai, bestiality takes on a new meaning with [furry] as well as the less niche [nekomimi] .

貝合わせ kai-awase (lit) "facing/opposite clams" Tribadism. i.e. the act of two girls getting pleasure from the friction of rubbing genitalia together by scissoring of the legs. Popular lesbian practice in Western pornography As for its effectiveness in real life - better ask someone more in the know...

拡張
kakuchou "expansion/enlargement"Applies mainly in the way of breast expansion [BE] in which the breasts suddenly expand for the usual reasons (spell, potion, science) in drawn or animated hentai (and sometimes mainstream anime - Negima being the main culprit), but would also refer to penis expansion [inkeihidai] - the same but for the male genitalia and clitoris enlargement [inkakuhidai]. Also refers to the fictional fetish in which liquids are applied by the vagina, mouth or anus, usually by an enema type device, to such an extent that the abdomen expands so the girl looks pregnant. This is usually portrayed as part of extreme S & M play with stereotypical lines such as "It's going to burst" etc.etc.
浣腸 kanchou "enema" Strictly refers to liquids applied rectally to induce defecation, but can also involve [expansion] and doesn't have to involve scatology [funnyou]. The enema is usually water, but in more perverse material can be urine (directly connected by catheter or from another), or even semen. It is usually portrayed as part of the submissive role of S & M - unlike urination [hounyou] which seems to take a more dominant role, the act of inducing someone to squirt liquids out of their anus is undoubtedly more embarassing and therefore submissive.
顔文字フェチ kaomoji-fechi "emoticon fetish" Pornography drawn using ASCII characters or involving characters originally drawn using ASCII. Hopefully more an amusing diversion rather than an actual fetish, but then again...
計測フェチ keisoku fechi "measurement fetish" Fetish involving the measurement of girls' anatomy and clothing. Not content with just vital statistics, measurements include clitoris length, vaginal depth and diameter, skirt and sock length, and of course, the famous [zettai ryouki]
けめこずり kemekozuri Soapland service in which a girl rubs lotion onto a man's body using her body but mainly her extensive pubic hair.
獣 kemono "beast" The Japanese word referring to humanoid beast type hentai. See [furry]
獣変身 kemono henshin "animal transformation" animated/drawn hentai in which a girl starts to change into a humanoid beast [kemono], usually with the acquisition of animal instincts, and, most importantly, mating behaviour. Often the results of some kind of "scientific experiment gone wrong" if the storyline feels it fit to give an explanation.

奇怪
kikai "strange/bizarre" A general word referring to several fetishes of the weird and (slightly less) wonderful, including: body modification [nikutaikaizou], [guro], egg laying [chinran], animal transformation [kemono henshin] and miscellaneous weirdness.
緊縛 kinbaku "tight bind" one of the words for traditional Japanese rope bondage, it describes the sexual act of typing a girl (or man) up using intricate rope patterns and designs in order to extricate maximum aesthetic beauty and also to stimulate the body. The word [shibari] is also used, but strictly it refers to the tying of anything using rope or twine, whereas kinbaku refers to sexual bondage.

筋肉
kinniku "muscle" Muscular girls. Female bodybuilders fetish - men who like their girls hard and muscularly defined like Miss Universe. Almost entirely drawn hentai, since there doesn't seem to be that strange niche of women in Japan that get obsessed with bodybuilding to insane proportions. And anyway, the exaggeration in drawn hentai is always to the advantage in this case. Presumably its the ample thigh muscles that are the key muscles in this case. Or perhaps some others that don't bear imagining..
近親相姦 kinshinsoukan "incest"Sex with someone related to you. One of the other mainstays of Japanese animated/drawn hentai as well as anime in general and even seems to pervade into their traditional stories as well. It doesn't seem that incest is less taboo than in other cultures, but there seems to be a thrill gained from the extra level of depravity that it offers. Sex with direct relatives has specific names: Mother Complex (マザコン）,Father Complex （ファザコン）, Brother Complex　（ブラザコン）, Sister complex　（シスコン）
汚い靴下フェチ kitanai kutsushita fechi "dirty under-footwear fetish" Fetish involving dirty shoes and/or socks. Don't ask.
子ガル kogal (lit) " child girl" Kogals are one of those unique kinds of girls that you see once in a while on manga or on a documentary that stick in your mind. Kogals are girls wearing outrageous clothes and makeup who tan themselves in salons until they are orange and wear bright white eyeliner. Sexually very loose and often become teenage mothers. Styles in kogal fashion change with the times depending on which idol is currently popular.
コンクール konkuru "contest" Any pornography involving contests. Can involve cat-fighting between girls or a straight sex contest - for example to see how many men one girl can bring to orgasm in a set time (real life) or to fill/drink a beaker of semen (fictional) It brings an element of competition into an otherwise dull sex scene and inflames the male competitive urge apparently.
小女子 koonago "Small girls". Also means "lancefish", incidentially. The opposite of [kyokan onna], involves tiny girls pleasuring their relatively giant partners in parts that only tiny girls can reach. Can involve urethral play and whole body handjobs. At its very worst can involve the swallowing of said girls or insertion into various orifices. Thankfully this hasn't made it to live action just yet.
言葉ぜめ kotobazeme "word play" Sex talk. To make a girl horny by talking dirty. Could also be used to refer to phone sex.
口内発射 kounai hassha (lit) " inside mouth firing" To come into a girl's mouth. I'm assuming that it refers to her shouting not to come inside her and ending up in her mouth, or various other meanings are also possible. (thanks to Lint for definition)
潜り椅子 kuguriisu "side door chair" A special chair in which a customer sits. There are holes in various places so that the girl can get underneath for [fellatio] etc.
食い込み kuikomi "to erode" Refers to pulling girls panties so that the material bunches thinly and then moving it back and forth in order to stimulate her. Otherwise known as "flossing"
くすこ kusuko Vaginal Speculum. Ties in with [iryou fechi], but generally refers to pornography involving erotic (if they really can be) gynaecological exams. I would guess the thrill comes from seeing a girl at their most vulnerable or to be at your most vulnerable. And of course, the following malpractice.
巨ちん／巨玉 kyochin/ kyotama "big penis/balls" Generally refers to male genitalia that are inhuman in proportion (i.e. over 1 foot/30cm in length, but increasing to sizes unimaginable). Surprisingly, they still fit inside a woman's vagina or anus with very little to spare outside. Can be either that large, or achieved by penis expansion [inkeihidai]. Large balls are obviously compatible with extremely copious volumes of semen on orgasm - allows one man/futanari [bukkake]
巨漢 女 kyokan onna "giant women" Giantess fetish - not only an animated/drawn fetish but also available in live-action form with the help of special effects. Involves women of stupidly large proportions (godzilla-like) towering above cities with vaginas the size of the Channel Tunnel having sex with normal men who could happily climb inside and have a tropical holiday. Basically refers to any pornography in which a size difference between the man and woman is more than 4:1
巨乳 kyonyuu "large breasts" Along with [bakunyuu] and [chunyuu] describe breasts that are large but in the natural range, and usually acheivable without resorting to cosmetic surgery. Doesn't stop girls who are smaller getting cosmetic surgery to become this size, of course... Often applies to [gravure idols] who can be amply endowed to this extent.

レモン lemon Same as "blue movie" in English - refers to material containing sexual scenes. Comes from the Japanese slang for a "loose woman"
ライム lime "softcore" an erotic piece, but no actual sex. Obviously a progression from "lemon" as in "slightly less immoral" - well, as immoral as citrus fruits get anyway.
ロリコン lolicon short for "Lolita Complex". Refers to the lust for underage girls. The term is actually Western and comes from the interpretation of the book "Lolita" by Vladimir Nabakov - a tragic comedy about the wooing and extraction of sexual favours from Dolores (Lolita) - a twelve year old widow's daughter - by an older man. Synonymous in most contexts with paedophilia, but some may argue that in reference to hentai, Lolicon refers only to fictional drawn sexual material and therefore lacking the corruption or abuse of real children. The distinction seems to be purely academic.

マンコ manko "pussy" - otherwise variously known as omanko, omeko and sometimes "hako" (box). Other seafood based references I think also exist.
#めがねっ子 meganekko "glasses girl" A rather specific genre in Japanese erotica in which girls wearing glasses are seen to be more attractive. Whether this is due to the glasses making them seem vulnerable and innocent or the reminding of high school days would probably vary from person to person. Nevertheless, meganekko are stereotypically bookish and shy and tend to play submissive roles.
目隠しプレ mekakushi pure "blindfold play" - any sexual act involving one of the participants being blindfolded (usually the submissive in S & M play) They say that being deprived of one of your senses heightens the other four. In that logic, noseplugs, earplugs and ballgags would leave a person in heightened sexual ecstasy comparable to Nirvana. If only life was that simple...
めりフェチ meri fechi "wet fetish" - I'm not sure of this one, since I can't find that "meri" means "wet" in the dictionary , but apparently refers to an AV fetish in which athletic girls are filmed doing various things wet - e.g. swimming naked, being hosed down, taking baths etc. Everyone knows that water and sex in real life generally results in slipping over and back sprains...
未亡人 mibojin "widow" - Generally refers to a woman widowed in middle age by a freak disease or car accident leaving an apprently very lonely and sexually frustrated woman in need of some special attention. Also ties in with "attractive middle aged lady" [jukujo]
耳フェチ mimi fechi "ear fetish" - fetish centering around women's ears. Like the tooth fetish [ha daisuki] I have absolutely no idea why this would be in the least bit sexy, but then again, for every part of girls, there are men who find them extremely erotic. I wouldn't be surprised if there was a "Philtrum fetish" in some backalley forum in the Internet somewhere.

水着
mizugi "swimsuit" Not exactly a fetish, since swimsuit competitions and magazine spreads are ten a penny in Japan. Includes all the usual Western styles - string bikinis, tankinis and [gravure idols] with [bakunyuu] strapped into impossibly revealing criss-cross string contraptions. The most famous swimsuit type of all is the school swimsuit (sukumizu), a blue one-piece type suit with the name emblazoned on the front in large letters on a white label and for some reason a hole in between the top and bottom only on the front of the suit (apparently for hydrodynamic reasons - see Ch14-15 of Gakuen Heaven for an explanation). Presumably also put there by the maunfacturers for easy erotic access, though in real life this would probably result in [lolicon] and a subsequent prosecution.
悶絶 monzetsu "fainting in agony" A minority fetish separate from [guro] which focusses on painful sex. Specifically in most cases, the sex is "so painful it's good" in that roundabout, semi-masochistic denial fashion that the Japanese have done so well. In manga, usually involves men with impossibly large manhoods and girls having sex so hard they throw up or pass out. Usually contains amusing phrases such as "you're going to tear my ovaries off" - skirting the line between hentai and comedy.

肉体改造 nikutaikaizou "body remodeling" Refers to a range of bizarre [kikai] fetishes involving the modification of bodies to a certain end through (usually) science or surgery. Can involve limb amputations (for example, [suitcase girls]), addition of extra breasts/genitalia, removal of same, addition of appendages, heads and other even more bizarre things impossible to mention without cringing. The turning of girls into everyday objects such as tables apparently originates from the novel "Kachikunin yapuu" (The Human Cattle) - for more information read [Hentai Dictionary]
中出し nakadashi (lit) " exit inside" To ejaculate inside your partner (either in the vagina or rectum) Also can be used as a verb - nakadashimasu = "I'm coming inside" Equivalent to the Western term "creampie". In animated/drawn material it is often elaborated by a cross-section/x-ray or subsequent pregnancy.
生 nama "raw" in this context used to indicate that a condom is not used. For example - nama-fera (blowjob without condom) nama-ecchi (sex without a condom). As opposed to gomu-fera (blowjob with a condom).
軟派 nampa "girl hunting". Commonly known as flirting in the West, but possibly in a more serious sporting sense, this is the "art" of picking up girls. As with all things that the Japanese have or take from other cultures, there has evolved a complex system of nampa complete with teachers, rules and "secret techniques". Generally, though, it consists of men standing on street corners and picking up women, sometimes for dates and sex and others for more long term relationships. The reverse in which women approach men is called "gyakunan" (逆ナン)
軟派盗撮 nanpa-tousatsu "secret flirt film" Nanpa-tousatsu refers to a man who secretly films the course of picking up a girl in a bar through to taking her to a love hotel room and having sex with her. Illegal of course, but if done as an act then marketable.
猫耳 nekomimi "cat ears" A special kind of cosplay in which the girl wears cat ears and sometimes a tail and responds with sentences ending in ~nya (equivalent to English "meow"), but generally having minimal other feline characteristics.. Catgirls have been popularised in anime culture since early days, so it makes sense that the nekomimi stereotype is rife in both animated and live action hentai and [Imekura].

ニューハーフ
newhalf Another word for a pre-op transsexual (see also [shemale]). Generally refers to a man who has had breast augmentation but who still has male genitalia. Newhalf may also refer to an individual who is physiologically of one gender but whose identity and personality is of the other. They may also crossdress [josou].
妊婦 ninpu "pregnant" - any hentai containing pregnant women. Also exists in niche Western pornography. Presumably the basis is that women can be extremely sexually disinhibited at times when pregnant and also in some circles the pregnant woman is seen as the height of womanliness and therefore extremely desirable. Probably a bit of both to be honest.
ニップルファック nipuru faku "Nipple fuck" Refers either to actual milk duct penetration by the penis or the act in which there is no actual penetration, but pleasure is achieved since the girl's breasts are very large and so involutes around the penis. Often linked with lactation [bonyuu] - completely fictional fetish (impossible in real life).
ノーパン喫茶 no-pan kissa "No panties cafe" - A kind of cafe popular in the 80s in which the waitresses wore short skirts and no panties and the floor was mirrored for...well, you can probably guess. Generally no sexual contact was allowed with the girls, though coffee prices were sky high (up to £4 a cup - almost Central Rome prices). Later on, rooms were put by out back for pricier interactions such as masturbation or blowjobs. There are hardly any left now. No-pan yakuniku and no-pan shabushabu restaurants also exist, amusingly.
塗りフェチ nuri fechi "painting fetish" Material in which a nude girl is painted in bright colours all over her body - presumably the painting itself is mildly erotic and the finished work is artful and contemporary (dependent on the skill of the artists of course). Now all that's left is to label it "Untitled woman (painted)" and leave it in the Tate modern.
女体盛り nyotaimori "female body presentation" - the act of presenting food on a girl's naked body to be eaten off. The food is usually sashimi or sushi. The girl must be trained rigorously to lie still without moving and may be given a cold bath beforehand to reduce skin temperature. In certain establishments, she may be tied up using [kinbaku]. Male models are significantly less popular (nantaimori 男体盛り)
尿道挿入 nyoudou sounyuu/ nyoudoufaku "urethral penetration"Another rare fetish involving the penetration of the (usually male) urethra with a variety of implements - including anal beads, dildos, vibrators and other penises. A popular theme in [futanari] as this allows the theme of urethral penetration to be explored without gay overtones. Most of the feats of penetration demonstrated in hentai are biologically impossible (without a strict training regimen, of course)

御釜 okama "gay" - refers to all gay men. (The word actually means "pot" or colloquially, "buttocks"). Effeminite gay men are generally referred to as "neko" (the same term as used for feminine lesbians). Dominant gays are referred to as "seme" (top) and submissive ones as "uke" (bottom). "Bara zoku" (rose tribe) refers to the quality of being gay (roses being the flower of choice for yaoi) see [yaoi]
お漏らし omorashi "peeing" Specifically refers to the discomfort of having a full bladder. "omoraishi fechi" is the attraction to girls/men who are hobbling around with a full bladder being deprived of a toilet, or gaining pleasure from being the one with the full bladder. "omoraishi pure" is a service offered in soaplands similar to [aka-chan pure] in which the punter wears a diaper in which they urinate which the girl then deals with as if she was his mother.
オナニー onani "Onanism" - masturbation of both male and female variety. Female masturbation is otherwise known as "manzuri" (ten thousand rubs) and "suichi o ireru" (flicking the switch). Generally known as "hitori ecchi" (sex on your own) or "hitorigokko" (self-play). See also [senzuri] for the male variety
屁/おなら onara "farting" Fetish involving girls, microphones, baked beans and several very embarassing sounds. May or may not involve the famous Dutch Oven (see Urban Dictionary). Lighting of said flatus optional.
おっぱい oppai "breasts" also known as: mune (胸 - chest) and chichi (乳 - breast, not to be confused with chinchin - penis). Refers to the female love pillows part of the anatomy, useful for cushioning falls, clearing space on trains and a refreshing drink on a cold day.
お尻 oshiri "bottom" - Referring to the part commonly known as the "ass" in American pornography. Other synonyms include: ketsu, dembu and oshiro ("behind"). The actual anus also has a variety of names including "ketsu no ana" (lit. ass hole) and kikuza (chrysanthemum). Oshiri is by far the most popular way of referring both to the fleshy and the hole part of the buttocks, though.
お書字 oshouji "calligraphy character" Fetish fairly commonly seen in Domination/submissive play in which the Dominant writes characters on the submissive's body in order to inflict shame and embarrassment to heighten the submissive role. Commonly seen is the writing of "niku" (肉 - "meat") on the forehead.
オウンゴウル own goal To ejaculate on one's own face. Often done as a submissive act - i.e. being tied up in a shoulderstand position with the legs over the head so that by virtue of gravity, the Dominant can watch the amusement of a man ejaculating on his own face. Also done with [futanari] girls.

パイズリ paizuri "tit-fuck" Comes from the "pai" of "oppai" (breasts) and "zuri" (onomatopoeia for a rubbing sound). Refers to a girl with large breasts stimulating a penis by rubbing it between them. If a [shemale] or [futanari] has a large enough penis and breasts, then she/he can do it to him/herself (autopaizuri)
パンチラ panchira "upskirt" Videos or still pictures taken of panties from a low angle in which the girl is wearing a skirt. Mainstay of anime fanservice, but popular in real Japanese culture in the 1960's when the mini-skirt became most popular. Either involves actresses pulling up skirts for the camera or amateur cameramen running around streets flipping skirts or filming under stairs and such.
パンツと顔 pantsu to kao "panties on face" The hilarious humiliation of girls or men by the putting of panties (often dirty) on the head so that the eyes show through the leg holes. In addition to the humiliation element, the thrill could also come from the smell of unwashed gusset and the mild asphyxiation caused by having too-tight panties blocking nose and mouth. Either way, it looks silly.
ペニバンド peni-bando "strap on dildo" from "penis" and "band" refers to devices used by lesbians to penetrate other girls, usually attached to the hips by a harness contraption, but can also be attached to the forehead or mouth (usually in bondage play where the submissive cannot move her hips).
ピンクサロン pink salon Also known as pinsaro ( ピンサロ)., Brothels specialising in oral sex. Apparently demanding places to work (building character, I would say!) but can act as stepping stones to more highly paid jobs in the Japanese soaplands.

ぽっちゃり
pocchari Similar to [debusen] refers to the fetish for larger women, though the exact meaning may differ - can refer to fat women, or large women with large breasts, chubby (i.e. not anorexic) girls or women that are clinically obese. Whatever floats your boat.

レスビアン
rezubian "Lesbian" (directly from the English) Also contracted as "rezu" (レズ ). Another word for material involving two women having sex or the subjects of said material. Butch lesbians may be known as "otoko onna" or man women (but that's probably fairly derogatory, so I wouldn't go using it in the streets). Feminine lesbians may be referred to as "neko" (cat). "riri zoku" (lily tribe) refers to the quality of being a lesbian (lilies being the lesbian flower of choice) See also [yuri].
リバシブル ribashiburu "reversible" Someone who can switch from Dominant to submissive roles. Knwon as "switch" in English Dom/sub slang

輪姦
rinkan "gangrape" Sex involving multiple partners in which men change sexual partners during the course of the act. Classic to Western pornography, scenes can involve double or triple penetration and various other things only possible with more than one. Remember, two's company, three's a crowd, but four is when you start to make the money.
リップシャヴィス rippu savisu "Lip Service" Refers to all sexual acts from kissing through French kissing to fellatio. Basically, anything involving lips can be termed "Lip service".
ルーズソックス ruzu sokkusu "loose socks" This refers to the infamous loose socks worn exclusively by Japanese schoolgirls from the 1990s. The socks themselves originated from American manufacturers, who were aiming at the mountain climbing industry, but the market for young high school girls became viable after they were adopted as an "alternate school uniform". It is not usual for other age groups to wear them - they seem to be exclusively high school. Also, since they are so loose, it is usual for girls to purchase "sock glue/adhesive" in order for them to stay up at all.

猟奇
ryouki "mutilation" defacing of a body using knives and other sharp objects - directly related to [guro] and can also be part of body remodeling [nikutaikaizou].

精水 seisui "spirit/holy water" - Euphemism for urine.
攻め seme "attack" Refers to the Dominant male in a gay [yaoi] relationship. Opposite to "uke". Usually indistinguishable in appearance since most yaoi is depicted as "pretty boy" or "bishonen", but in real life usually refers to the masculine rather than effeminate man. See [neko]
潜望鏡 senbokyo "periscope" Fellatio in the bath. Hilarious, I know. If you've ever heard of the term "Spot the submarine", you'll know what this is talking about. In this soapland practice, the girl takes a bath with her customer who flexes up at the hips so she can bend over and fellate him. Gotta make sure there's no soap though - tastes disgusting...
千擦り senzuri "thousand strokes" - male masturbation. Also known as "shiko shiko" - onomatopoeia for the Western equivalent of "Fap fap". See also [onani] for the female connotation.

シーメール
shemale "shemale" similar in meaning to [newhalf]. Refers to either a male possessing distinct female personality and physiological characteristics, or a pre-op transsexual male who has received breast augmentation but still retains male genitalia. Comes directly from the Western term.
縛り shibari "to tie" Refers to any act of tying or binding with string or rope and has only recently passed into use for meaning the specific Japanese style of bondage in which the recipient is bound with intricate patterns of interweaving hemp or jute ropes restricting movement and promoting pain or pleasure. See also [kinbaku]. Interestingly, though Western bondage favours knots, traditional [kinbaku] has no knots at all, and modern versions make do with only simple knot types.
屍姦 shikan "necrophilia" Lust for dead bodies. Can be associated with [guro]. Technically, necrophilia refers to sexual acts done on bodies already dead, rather than the killing of same. I have no idea why this would be attractive but then again, I can't empathise with the guro people either I suppose "not wanting to let go of a loved one" + a little sprinkle of madness might explain it, or perhaps having complete control over someone's body.
真珠 shinju "breast bondage" - referring to [kinbaku] type Japanese bondage applied to the breasts in which ropes entwine around the breasts, under the arms and back in such a way that they are squeezed in a stimulating way when the victim struggles. Also, it looks neat. As said before, it is rare for knots to be used in this kind of bondage.
潮吹き shiofuki "geyser/whale spouting" Female Ejaculation - another great euphemism where the Western terms are lewd and crude and the Japanese term is...fairly obscure to those not in the know. If "shiofuki" is expected, it is customary for the customer to shout "Thar she blows!" as it occurs. Actually, that is a lie.
したぎまニャ shitagi mania "panty mania" - obsession with panties. Not the dirty kind - the normal kind. (As opposed to [yogoreta shitagi] )

触手
shokushu "tentacles" Tentacles are a specific kind of bizarre [kikai] fetish specifically embodied in the landmark hentai Urotsukidoji in 1987 (First appearing in 1984 in "Obyoki Aki-chan" and "The Satisfaction") as a method of getting around the strict Japanese censorship laws in which showing a woman getting penetrated by a man was BAD but getting raped by an octopus of mechanical appendage was A-OK. However, they did exist in Japanese erotic art and literature long before then - specifically in an 1820 woodcut print "Dreams of a Fisherman's Wife" which involved a woman, one, no sorry, two octopi and... well, you can imagine the rest. So tentacle porn is well entrenched in Japanese culture and the progression to hentai seems to be more natural rather than revolutionary. Aficionados of the genre cite that the eroticism comes from the image of a girl being pleasured in many ways at the same time - otherwise impossible in real life due to steric hindrance.

ショタコン
shotacon The opposite of [Lolicon], "shotacon"is a contraction of "Shotarou complex" of which "Shotarou" is a character taken from an old manga/anime series "Tetsujin 28-go". In this series Shotarou is a young boy who nevertheless displays adult personality traits and works in the world of adults. "Shotacon" itself refers to people who prefer young boys (otherwise known as "Grecian love") There are several types of shotacon, perhaps most commonly involving middle aged women and young boys or older men and young boys (more reminiscent of ancient Greek culture). It can also be used to refer to relationships depicted between underage girls and boys. Themes can involve cross dressing [josou].
春画 shunga Erotic wood block prints (ukiyo-e). Similar to the fashion in Europe in the early days of printing, where saucy French lithographs circulated amongst the gentry for masturbatory purposes (though their content would hardly even make post-watershed these days), in Japan there were similar affairs with their particular traditional art - ukiyo-e (basically, if you've seen classical Japanese art like the waves crashing or Mount Fuji, it's ukiyo-e). Presumably, this also included [shuudo] related depictions. One might say this was the beginnings of the fanbase for yaoi fangirls...
衆道 shuudo The age-related structure of homosexuality in the Samurai period. Shuudo means "way of the young" and the system itself was similar to the oft-quoted mentoring systems of old in which older men befriended and sponsored younger boys who became their lovers as well as almost their sons (otherwise known as pederasty). The Japanese samurai had a similar tradition and it was strange for a man to say that he wasn't with a young man in this way rather than vice versa. It also had a great following in the literature and the arts, with hundreds of titles published on the subject as well as some very saucy woodblock prints for the masturbatory pleasure of the ancestors of today's yaoi fangirls.
ソープランド sopurando "soapland" - in any other country known as a brothel, soaplands exist at the very heights of the Japanese adult services (what all little prostitutes want to do when they grow up) - They are specifically brothels offering girls to wash a man for a fee as well as several other services revolving around sexual gratification ( but not including vaginal penetration). This is again to work around the loophole-filled Japanese prostitution laws which specifically prohibit the exchange of money for vaginal penetration. Darn bureaucrats and their clean minds!
素股 sumata "intercrural sex" or "femoral intercourse" - A service at soaplands, and occasionally seen in hentai as well - the intercrura refers to the space between the thighs when the legs are held together - i.e. holding the girl's legs together while the penis is masturbated between them. A kind of "thigh-wank" if you will. Popular amongst customers who shied away from actual penetrative sex. After all, if it's not in, you're not cheating...
スッポン suppon Vaginal spasm - You can imagine this onomatopoeia. Girl: "Ah, ah! Iku!!!" SUPPON

玉蹴り tamakeri "ball kick" Either the masochistic act of gaining sexual satisfaction from having a beautiful lady kick you in the testicles or the sadistic act of gaining sexual pleasure from watching beautiful girls kick other poor men's testicles. Presumably, there is an element of panty flashing involved, but I would say that this nestles safely within the S & M category of fetishes.
玉嘗め tamaname "ball lick" - To lick the balls.
剃毛 tei-mou "shaving" - In soaplands, this refers either to having your pubic hair shaved or shaving the girl's pubic hair. I wouldn't say that this was an S & M act - if anything, it would be more towards Dom/sub since it involves a rather large modicum of trust.
手コキ tekoki "handjob" - exactly what it says on the tin - to bring a man off with the hands. As opposed to [ashikoki] which is obviously "footjob"
テレクラ terekura "telephone club" - similar to the Western "dating hotlines" advertised in the glossies and late at night on Channel 5 (I can only assume it's advertised all the time on American cable), in which you call up and talk to an ugly girl with a sweet voice for 2 minutes and get charged fifty pounds. In Japan, these are often fronts for the aforementioned teenage prostitution [enjo-kosai] as methods for older balding businessmen with busy lives and wives who don't put out to meet horny young schoolgirls with a penchant for plastic.
唾シャンプウ tsubashanpu "spit shampoo" - Another Ronseal kind of fetish - although rather than the traditional girl sitting while men spit on her in a degrading, bukkake-esque scene, this refers to a fetish in which the man is held down and spat on by girls and women. Obviously, this preys on secret fantasies of submission and has several advantages over bukakke - the most obvious of which is that it tastes somewhat better and it doesn't take multiple lather-rinse-repeats to get out in the shower afterwards.
壺洗い tsubo-arai lit"pot washing" - i.e. washing the vagina of your girl with soap and fingers. Part of the whole "sex in the bath" kind of fetish. The fact that the Japanese seem to spend most of their bathtimes out of the bath seems to lend itself to immoral goings-on anyway...

受け uke/ukemi "bottom/receiver" - the opposite of [seme]
裏本 urabon uncensored sex book
後ろ高手小手 ushiro takatokote (lit) " behind high small hands" - the basic form of [kinbaku] in which the hands are bound behind the back so that the hands touch the elbow of the opposite side.

わかめ酒 wakamezake "seaweed sake" The act of drinking sake from the depressions in a woman's body. One would envisage the appropriate points would be the depression of a sucked in stomach, from between breasts squeezed together and from the crotch with the thighs pressed together. Advocates of this would probably say that the sake takes on the womanly flavour and becomes a delicacy, but basically, it is a variation of the eating food off women fetish [nyotaimori] but with less presentation and more tongues.
ヲバリスト wobarisuto "rubberist" - one who likes to dress in rubber. Intimately associated with the Western BDSM culture, this commonly involves either Dominant men or women dressed in tight fitting rubber catsuits or submissives totally encased in rubber with only small holes for breathing (under the Dominant's control). You can imagine that there are many ways in which this would stimulate - to name but a few: complete trust submission, sensory deprivation, erotic-asphyxiation etc. etc.

野外 yagai "outside" To perform a sexual act in public. This doesn't have to be sex, but also includes urination, masturbation and public nudity. In this, the thrill for the man comes from the embarrassment of the girl and the domination of getting her to do unpleasant things or alternatively the voyeurism of watching public indecency. For the girl, there is usually a degree of exhibitionism deriving pleasure from embarrassment or a thrill from almost being caught.
やおい yaoi short for "yama nashi, ohi nashi, imi nashi" or "No climax, no punchline, no meaning" (though I would guess that most gay people you meet would tell you different!), refers to sex between men. This can take 2 main forms - Older man seducing younger inexperienced boys (similar to [shuudo or two bishonen (pretty boys) depicted as in a sexual relationship - much to the chagrin of the entire female cast. Yaoi is older and more popular than yuri (the female equivalent, discussed below) and you'll find yaoi fangirls in the strangest places. For some reason, it seems to appeal more to girls than gay men. The equivalent in Western fandom is "slash" which encompasses both gay and lesbian pairings.
やりまん yariman "slut" - apparently one of the rudest words in Japan. It's probably short for "doing it" and "10000" - as in "done it 10000 times", but still lacking in a reference for that.
夜這い yobai lit: "night crawling" i.e.To sneak into your girlfriend's bed to have sex. Much like the Milk Tray man in Western Folklore.
汚れた下着 yogoreta shitagi "dirty panty fetish" men who like used panties. There is in fact a thriving trade in used panties in Japan, the most famous of which are the "Used Panty Vending machines" in Tokyo, where you can buy panties guaranteed used by Japanese schoolgirls. Shady backstreet vendors will also sell these, often with pictures of the girl on the front, so you can see what you're getting. In soaplands, service might include a girl taking off her panties for you and you either (paying a fee to) take them away or having her smell them . Needless to say, soiled panties (blood, urine, etc.) are probably worth more. In fact, you can sometimes ask for your attendant's urine to take away when you visit a brothel (known as "teiku auto" )
百合 yuri "lily" - referring to lesbian relationships. Naturally, the opposite of yaoi. Yuri gets its name from the lily flower, which is white and pure - reflecting the purity of girls who shun men and therefore keep their virginity. The equivalent flower for yaoi is the rose. Also, it has two syllables, starts and ends with the same sounds and was coined after [yaoi]. As with yaoi, there are two main storylines - Sempai (upperclassman) seducing vulnerable young girls in the years below and just the plain girls of the same age group falling in love. Yuri has a much smaller fanbase than yaoi and seems to appeal both to girls and men. Catholic schoolgirls and childhood friends are common yuri fodder.

全裸 zenra "completely nude" - not unusual in pornography, you might say. Zenra refers to material in which girls are seen doing things that they would do everyday, such as vacuuming, going to work, talking on the phone etc. but completely nude. Similar in vein to the fetish in which girls are photographed in only one piece of clothing [hadaka]