Following the introduction of the Motion Picture Association of America film rating system, independent animation producers attempted to establish an alternative to mainstream animation. Many times a top actor will then be sought as a bottom and the debut is often treated as a notable event or even its own release. Among fetishists, the pose of reluctance—the victimization of the cuckold—is a major element of the paraphilia. Although there may be no connection between coprophilia and sadomasochism , the limited data on the former comes from studies of the latter. Such works have also often been subject to censorship and other legal restraints to publication, display hot gay sex 3d hentai porn or possession. Mammary intercourse has sometimes been considered a perversion. Such documents have not been recognized as being legally binding, nor are they lesbian milfs intended to be. Before the enforcement of the Hays Code, some cartoon shorts contained humor that was aimed at adult audience members rather than children. Clothed female, naked male pornography features naked men and clothed women; typically, the women humiliate and hentai movies abuse the men or perform fellatio and/or handjobs on the men. No causal relationship is known between masturbation and any form of mental or physical disorder. Some masturbate only using pressure applied to the clitoris without direct contact, for example by pressing the palm or ball of the hand against underwear or other clothing. The current public acceptance of celebrities with sex tapes is speculated by Joe Levy, executive editor of Rolling Stone, to be due to the easy availability of pornography, as well as couples more commonly making their own tapes due to the prevalence of video cameras. The activity is done by itself or as a part of or prelude to other activities which many times involve sex. As the pro naked celebrities state is touch-sensitive, some directly stimulate it using a well-lubricated finger or dildo inserted through the anus into the rectum. The naked appearance of actress Demi Moore in the advanced stage of pregnancy on the cover of Vanity Fair magazine in 1991 marked the beginning of a period which has since seen pregnancy presented by celebrities as a glamorous state of living, while also creating a market for photographers to produce images of pregnant mothers, and for fashion stylists to introduce pregnancy styling to their business.