It contains graphic sexual activity and visible penetration. Diaper pornography involves performers wearing diapers, sometimes with an adult performer acting in the role of a caretaker. People may engage in anilingus for its own sake, before anal fingering or penetration, or as part of foreplay. Even though the performers who perform in these films typically appear on many reality websites within a short span of time, most of these websites claim that each of them is an amateur. Starting with erotic stories and woodblock prints from before the 20th century, Japanese pornography evolved into distinct subcategories with the media that in addition of pornographic videos and magazines featuring live actors, there is exist categories of pornographic manga , pornographic computer games , and pornographic anime . A variant of A2M is ATOM where a performer inserts his penis directly from one recipient anus into a second recipient mouth. Sadomasochism hentai movies is practiced in isolation relatively rarely, though some masochists report biting, pinching, or even stun-gunning themselves as a prelude to, or as part of, masturbation. The reverse of this, in which nude women interact with clothed men, is called Clothed male, naked female . Oral sex pornography milf xxx frequently features a person performing fellatio, and less frequently cunnilingus. Kinbaku means tight gaysex binding Kinbaku-bi which literally means the beauty of tight binding. Reality pornography is professionally made porn which seeks to emulate the style of amateur pornography. Some may keep their hand stationary while pumping into it with pelvic thrusts in order to simulate the motions of sexual intercourse. Individuals are also sometimes abbreviated when referred to in writing, so a dominant person may be referred to as a Dom for a man, and a Domme for a woman. Foot fetish pornography features heavy emphasis on the feet of the participants, either in combination with kissing and genital sex or in the context of acts such as trampling or crush fetishism.