The activity is done by itself or as a part of or prelude to other activities which many times involve sex. Rimjob pornography centers around anilingus. Before the enforcement of the Hays Code, some cartoon shorts contained humor that was aimed at adult audience members rather than children. Point of view pornography is adult entertainment filmed to look as if the watcher were experiencing the sex act themselves. Sadism describes sexual pleasure derived by inflicting pain, degradation, humiliation on another person or causing another person to suffer. Typically, its fans identify themselves as straight. Behind the Green Door was one of the first pornographic films to feature hentai movies sex between a white actress with a black actor . Studies among BDSM practitioners in the US have shown that about half of all men find the idea of bondage to be erotic; many women do as well. Threesome or 3some pornography features one man and two women . Following the introduction of the Motion Picture Association of America film rating system, independent animation producers attempted to establish an alternative to mainstream animation. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. Smotherboxes are usually custom made pieces of furniture that may have a special significance for their users. A related term used in the genre is the term cougar, milf xxx which implies an older woman as predator. Individual tastes and preferences in the area of sexuality may overlap among these areas, which are discussed separately here. As women, they face concerns separate from videos gays men. Some may pursue fantasies that are concerned with the circumstances in which a subject may give birth, or to the conditions to which the pregnant subject may find themselves acting upon, such as approaches to mobility, sleeping, and dressing. Gonzo pornography is a style of pornographic film that attempts to place the viewer directly into the scene.