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. The genres of pornography are based on the type of activity featured and the category of participants, for example mateur pornography is a category of pornography that features models, actors or non-professionals performing without pay, or actors for whom this material is their only paid modeling work. Watersports pornography features sexual activities involving urine, such as golden showers. The scenario is a genre of erotica, which on the internet is sometimes abbreviated to CMNF, and may involve sexual and nonsexual erotic scenarios. It may be used as foreplay, or as an alternative to sexual penetration. Heterosexual bareback sex, as opposed to sex with condoms, not only poses an increased risk of STIs, but for pregnancy as well. As a result, little in history was documented to give an accurate description of how female homosexuality is expressed. Diaper pornography involves performers wearing diapers, sometimes with an adult performer acting in the role of a caretaker. When sexual activity is centered on one of the threesome, then the activity may be described as a gang bang of the person. The term soft crush refers to the more common fetish surrounding videos involving inanimate objects or small invertebrates being crushed, while the term hard crush refers to such videos involving larger animals with vertabrae, and arguably more pain-susceptible animals . Tentacle rape or shokushu goukan is found in some horror or hentai titles, with tentacled creatures having sexual intercourse with female characters. First found in softcore movies and 3d hentai erotic thrillers, depictions of lesbianism entered mainstream cinema in the 1980s. These scenes may involve the female actor calling for the shot gay fuck to be directed at horny milfs some specific part of her body. Mutual masturbation can be practiced by males or females in pairs or groups with or without actually touching another person as indicated by the following examples of contact versus non-contact scenarios: Non-contact mutual masturbation Two people masturbating in the presence of each other but not touching.