Preggo pornography features pregnant performers and may include erotic lactation as a fetish. Bukkake pornography involves a performer, usually female, onto whom several men or women ejaculate, usually on the face. Exhibitionism: Becoming noticeably desperate or wetting oneself with the express purpose of being seen by strangers. His most famous model was Bettie Page, who became the first celebrity of bondage film and photography. It is geared towards heterosexual men, who most typically define a threesome as such. During anal gay movies sex, male pleasure can be particularly derived from the prostate, which can lead to an orgasm and ejaculation. In humans, females generally have more round and voluptuous buttocks, caused by estrogen that encourages the body to store fat in the buttocks, hips, and thighs. The activity is done by itself or as a part of or prelude to other activities which many times involve sex. Perhaps following the example set by gay pornography, they have become a popular subgenre within heterosexual pornography since the turn of the century, featuring both vaginal and anal ejaculations. 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. Common anime hentai phrases used to refer to these individuals are chicks with dicks or the derogatory term shemale, although these are generally considered pejorative among transwomen. The introduction of the home video and Internet saw a boom in the worldwide porn industry that generates billions of dollars annually. Following World War II, during a period of social repression when governments lesbian milfs actively persecuted homosexuals, women developed networks to socialize with and educate each other. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. Such works have also often been subject to censorship and other legal restraints to publication, display or possession.