Nevertheless, it is only an attempt at phenomenological differentiation. Reality pornography is a genre of pornography where staged scenes, usually shot in cinéma vérité fashion, set up and precede sexual encounters. Some pornographic films use an artificial semen substitute to simulate or enhance porn milf creampie shots. See also Gay-for-pay. Concerted deployed sexual rejection exercised on the partner can be an aspect of Dominance and Submission as well. A lesbian is a female homosexual; a female who experiences romantic love or sexual attraction to other females. This type of pornography is almost exclusively hentai, as true hermaphroditic humans are not fertile and are not usually found in nature. Lesbian pornography typically features a wider range of appearances and body types than is typical of mainstream pornography. Sadism describes sexual pleasure derived by inflicting pain, degradation, humiliation on another person or causing another person to suffer. It is geared towards heterosexual men, who most typically define a threesome as such. Snowballing or snowdropping is the human sexual practice in which one person takes someone else semen into his or her mouth and then passes it to the mouth of the other, usually through kissing. 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. Rubber pornography involves rubber, latex, gay hentai and similar materials. In contrast, a celebrity may take the route of openly releasing the tape and benefit directly from royalties as well as indirectly from the publicity. The volume of semen that is ejaculated depends on several factors, including the male health, age, degree of sexual gaysex excitement, and the time since his last ejaculation. Women with women Main article: hentai porn games Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience.