Making a pearl necklace is one of the activities that sex workers use as safe sex alternatives for people who refuse to wear condoms. Given the wide range of practices, some of which may be engaged in by people who do not consider themselves as practicing BDSM, inclusion in the BDSM community or subculture is usually dependent on self-identification and shared experience. 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 is a slang word that originated in the gay community and comes from the equestrian term bareback, which refers to the practice of riding a horse without a saddle. Erotic literature and pornographic films have been devoted to the sexual uses of glory holes. In pornography, depictions of lesbian sex form a popular subgenre, directed toward horny milfs a male heterosexual and female homosexual audience. Am Abend , one of the earliest pornographic films that have been collected at the Kinsey Institute for Research in Sex, Gender, and Reproduction, starts with a female masturbation scene. Clothed female, naked male is a genre of erotica featuring one or more nude men and one or more clothed women. Anal sex or anal intercourse is generally the hentai videos insertion and thrusting of the erect penis gay boy porn into a person anus, or anus and rectum, for sexual pleasure. Cum-shot pornography features a collection of male ejaculation scenes. Exhibitionist pornography features performers, usually female exposing themselves in public and spans simple flashing to public sex. Men and women may masturbate until they are close to orgasm, stop for a while to reduce excitement, and then resume masturbating. Individuals who can change between top/dominant and bottom/submissive roles—whether from relationship to relationship or within a given relationship—are known as switches, though the term switch in this context is occasionally seen as derogatory and is rejected by many who might simplistically fit the definition.