Anime clearly marked as "Restricted 18" material centring on all variations of adult sex, some of which can be considered as quite perverted.
Hentai — Subcategories
Sodomy, buggery, buttsex, cornholing, or the poop-chute polka. Call it whatever you like, but somebody is getting something stuck where the sun does not shine.
A form of "kinky sex". The acronym BDSM derives from BD (bondage and discipline), DS (dominance and submission) and SM (sadism and masochism). BDSM usually characterizes with one side being superior (active) over the other (passive), with each side being one or more participants. Whips, chains, handcuffs, ropes, blindfolds are common elements of BDSM.
Bondage is the use of restraints for the sexual pleasure of the parties involved. It may be used in its own right, as in the case of rope bondage and breast bondage, or as part of sexual activity or BDSM activity.
Depiction of defecation. Could be something minor as a burst of brown liquid caused by an enema or something major like actual eating of pieces of excrement.
A long stick-like device, usually slightly flexible, with a small bit of leather or cord, called a "popper", on the end. Depending on length and flexibility, this type is often called a riding whip, riding crop or "bat". It is also sometimes called a "horsewhip" or "horse whip".
Chikan (痴漢) is the Japanese term for non-consensual frotteurism which in common speech means groping. The men who commit such acts are also called chikan, the term for women is chijo (痴女). Crowded trains are the most common target of chikan and chijo and majority of hentai that feature chikan take place on trains; therefore in AniDB terms, chikan would mean "groping on a train".
- Examples: Uba
Dildos - Vibrators
Yaoi refers to anime that portray gay (male/male) sex. Do not confuse this with the Shounen Ai category under Romance, which only portrays male/male relationships, but generally not anything pornographic. This is real male/male porn.
Yuri refers to anime that portray lesbian (female/female) sex. Do not confuse this with the Shoujo Ai category under Romance, which only portrays girl/girl relationships, but generally not anything pornographic. This is real female/female porn.