Anime clearly marked as "Restricted 18" material centring on all variations of adult sex, some of which can be considered as quite perverted.
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.