Unlike erotic films, pornographic films contain explicit sexuality and do not claim any artistic merit. In pornography, depictions of lesbian sex form a popular subgenre, directed toward a male heterosexual and female homosexual audience. 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. Other possibilities are possible, such as a man having sex with two women who are having sex with each other. Klaw ran an international mail-order business out of his store, Movie Star News, selling cheesecake pinups and bondage/spanking photos. This is commonly called double anal or double stuffing. The stimulation may involve hands, fingers, everyday objects, sex toys or combinations of these. It may be used as foreplay, or as an alternative to sexual penetration. A variation on this is to place the fingers and thumb on the penis as if playing a flute, and then shuttle them back and forth. A variant of A2M is ATOM where a performer inserts gay movies his penis directly from one recipient anus into a second recipient mouth. Generally, interest differs between people, and gender depends on sexual orientation. Using the term shemale for a transsexual woman often implies that she is working in the sex trade. Transsexual pornography features transwomen performers, who typically have male genitalia and augmented female breasts . Internal ejaculations, lesbian hentai 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 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. Mammary intercourse is said by Alex Comfort to produce mutual orgasm in women with sensitive breasts , and it was one of the nine substitute exercises for penetrative sexual activities, as detailed in the Paradis Charnels of 1903.