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. Gay pornography is the representation of sexual activity between males. Breast fetishism is a paraphilic sexual interest focused on female breasts . Certain websites have begun providing bondage videos and photographs featuring the kidnapping roleplay, which has been largely the hallmark of detective style bondage magazines. Since mammary intercourse is a non-penetrative sex act, the risk of passing a sexually transmitted infection that requires direct contact between the mucous membranes and pre-ejaculate or semen is greatly reduced. The consensual submission gayporn of the submissive is sometimes demonstrated to others by symbols indicating his/her belonging to the dominant, such as wearing a collar, special tattoos, piercings, a very short haircut or a bald head. Reading or viewing pornography, sexual fantasy or other erotic stimuli may lead to a desire for sexual release such as by masturbation. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. The study also found that participants reacted positively to a much wider range of figures than a control group, even rating emaciated figures higher. The term comes from the French voyeur, one who looks. Such documents have not been recognized as being legally binding, nor are they intended to be. Diaper fetishism, nappy fetishism or diaperism, is a sexual fetish in which a person feels a desire to wear or use diapers. During anal sex, male pleasure can be particularly derived from the prostate, which can lead to an orgasm and ejaculation. Some people masturbate by using machines that simulate intercourse. Behind the Green Door was one of the first pornographic films to feature sex between a white actress with a black actor . 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.