Going back at least as far as the Christy twins in the 1970s, depictions of incest and particularly incest between twins has been a feature of gay pornography. The work of Bruce Seven has been called reality porn, due to his lack of using scripts and asking his performers to act naturally in their own character. Related genres include: Amateur pornography originally referred only to pornography produced by amateurs but now also includes professionally made pornography designed to appear as if it were amateur. Another variant of reality pornography consists of normal couples that are filmed by professionals, in which case the only obvious distinction from amateur pornography is the higher quality of production, filming and editing. Facial cum shots are currently regularly portrayed in pornographic films and videos, often as a way to close a scene. Crying pornography that features participating actors crying. Bara male homosexual hentai designed to appeal to men. The person sat upon may be in bondage, sexually submissive, or simply held down by the body-weight of the other person. Can also include auto-fellatio, or performing oral sex on oneself. While bondage is a very popular variation within the larger field of BDSM, it is nevertheless sometimes differentiated from the rest of this field. The first pegging scene appears to have been in the non-pornographic 1970 film lesbian hentai Myra Breckinridge, based on the novel of the same name by Gore Vidal, although it was not explicit. A variant of A2M is ATOM where a performer inserts his penis directly from one recipient anus into a second recipient mouth. A pearl necklace is a slang term referring to a sexual act in which a man ejaculates semen on or near the neck, chest, or breast of another person. A variation horny milfs on this is to place the fingers and thumb on the penis as if playing a flute, and then shuttle them back and forth. Fisting pornography features the insertion of an entire hand gay twinks into a performer vagina or anus. English adopts and uses hentai as a genre of pornography by the commercial sale and marketing of explicit works under this label.