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. Mutual masturbation is a sexual act where two or more people stimulate themselves or one another sexually, usually with the hands. These agreements are binding in the sense that the parties have the expectation that the negotiated rules will be followed. Sub-genres of Japanese porn Among the various sub-genres of Japanese pornography are the following: Lolicon ロリコン: This genre involves prepubescent and adolescent girls between the aged of 6-12. Lucky Pierre is slang for a person performing both receptive and insertive anal and/or vaginal sex simultaneously during a threesome, being positioned between the two partners. 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. Originating in Japan in the 1980s, the genre subsequently spread to North America and Europe, and crossed over into gay pornography. Enema pornography involves adults given enemas to others, often fake. People may engage in anilingus for its own sake, before anal fingering or penetration, or as part of foreplay. Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. Fantasies of group sex are extremely common among both men and women, and group sex is a subgenre in pornographic films. Big Beautiful Woman is a euphemism for an overweight woman and is frequently used gay videos in the context of fat fetishism. The terms can be complimentary or pejorative. Shemale is a term primarily used in sex work to describe a trans woman with male genitalia combined with female secondary sex characteristics, usually including augmented female breasts, from breast augmentation and/or use of hormones.