Internal ejaculations, followed by images of semen dripping from the anus, are sometimes depicted in bareback gay pornography, where they are referred to by the term breeding or the reverse money shot. A female dominant in a master/slave relationship is often termed a Mistress, not to be confused with the colloquial usage of mistress as a kept sexual partner without a similarly formalized power relationship. Guro or Gore is a genre of Japanese pornography involving blood, gore, disfiguration, violence, mutilation, urine, enemas, or feces. Some do not use the diapers at all, for arousal, or bladder and bowel movements. Reflective of its views on sexuality and culture, Japanese pornography delves into a wide spectrum of heterosexual, homosexual, and transgender sexual acts in addition to unique fetishes and philias. Some couples use pornography at times for variety and to create a sexual interest or as part of foreplay. Body parts including fingers, tongue and penis may be used for anonymous oral, vaginal and/or anal intercourse. Going back at least as far as the Christy twins in the 1970s, depictions of incest and particularly incest between twins has gay videos been a feature of gay pornography. The buttocks in human females thus contain more adipose tissue than in males, especially after puberty. A variant of this is known as ATOM or ATOGM where the insertive partner removes his penis from one recipient anus and inserts it into a second recipient mouth. The principal characteristic of voyeurism is that the voyeur does not normally interact directly with the subject of his/her interest, who is often unaware of being observed. But starting with The World Biggest Gangbang , starring Annabel Chong, the pornographic industry began producing a series of films ostensibly setting gangbang records for most consecutive sex acts by one person in a short period. Enema pornography involves adults given enemas to others, often fake. Foot fetishism, foot partialism, foot worship, or podophilia is a pronounced sexual interest in feet.