Threesome or 3some pornography features one man and two women . Common phrases used to refer to these individuals are chicks with dicks or the derogatory term shemale, although these are generally considered pejorative among transwomen. Pornographic films are typically categorized as either softcore or hardcore pornography. Those with diaper-related paraphilias differ widely in their focus of attention. Some pornographic films use an artificial semen substitute to simulate or enhance creampie shots. The most successful animated features produced in the United States primarily for adult audiences were directed by Ralph Bakshi, including Fritz the Cat, Heavy Traffic and Coonskin. Gonzo pornography is a style of pornographic anime hentai film that attempts to place the viewer directly into the scene. Some people masturbate by using machines that simulate intercourse. Instead, all five fingers are kept straight and held as close together as possible , then slowly inserted into a well lubricated vagina or rectum. Patricia Hill Collins, an African-American writer, theorizes that this is derived from a gaysex stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result. Bondage pornography specializes in the depiction of sexual bondage or BDSM activities as photographs, stories, movies, or drawings. Reading or viewing pornography, sexual fantasy or other erotic stimuli may lead to a desire for sexual release such as by masturbation. Shotacon : Similar to Lolicon, this genre involves prepubescent or under-aged boys between the ages 6–12. Female masturbation involves the stroking or rubbing of a woman vulva, especially her clitoris, with an index or middle fingers, or both. The lesbian milfs Girls Gone Wild series is one example. The neologism pegging was popularized when it became the winning entry in a contest in Dan Savage Savage Love sex advice column, held after an observation was made that there was no common name for the act. Its gain in prominence has been attributed to its depiction in the film Pecker, which was released in 1998.