English adopts and uses hentai as a genre of pornography by the commercial sale and marketing of explicit works under this label. The rise of the Internet in the late 1990s and early 2000s similarly changed the way pornography film was distributed and furthermore complicated the censorship regimes around the world and the legal prosecution of obscenity. Female dominance refers to BDSM relationships and BDSM scenes in which the dominant partner is female. The term hentai is never used in this context in Japanese. These agreements are binding in the sense that the young gay porn parties have the expectation that the 3d hentai negotiated rules will be followed. This may help them develop their orgasm, increase its pleasure, and may inspire them to masturbate on a more frequent basis. Such explicit sexual interaction is seen only rarely in public play spaces, and it is sometimes specifically banned by the rules of a party or playspace. Sex parties may be organized to enable people to engage in casual sexual activity or for swinging couples or people interested in group sex to meet, but any gathering where sexual activity is anticipated can be called a sex party. Although interracial pornography theoretically can apply to depictions of sexual activity between performers of any different racial groups, the term is most commonly used for heterosexual sex acts between black and white performers. Sexologist Alfred Kind suggested that the buttocks is the primary sexual presentation site in primates. The range of its individual momsex characteristics is thereby wide. Pornography may be presented in a variety of media, including books, magazines, postcards, photographs, sculpture, drawing, painting, animation, sound recording, film, video, and video games. The strategies and tactics that are used to smuggle one of the couple into and out of the toilet undetected are as important or almost as important as the urination. Sadomasochism 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.