The effect is to give the viewer the sense that they are experiencing the sex acts that they are watching, as opposed to simply watching others as a voyeur. Given the wide range of practices, some of which may be engaged in by people who do not consider themselves as practicing BDSM, inclusion in the BDSM community or subculture is usually dependent on self-identification and shared experience. Anti-pornography psychologist Ana Bridges and colleagues conducted a content analysis of best-selling gay movies heterosexual pornographic videos showing that over 96% of all scenes concluded with a male performer ejaculating onto the body of his female partner. 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. The sub-genres usually conform to certain conventions, and each may appeal to a particular audience. Facial cum shots are currently regularly portrayed in pornographic films and videos, often as a way to close a scene. Solo pornography features performers masturbating. For other diaper fetishists, simply wearing a diaper, the bulking feeling and crinkling sounds associated with it, is enough to cause the fetishist a form of erotic pleasure or sexual arousal. In straight pornography, intercourse is often followed by a facial, pearl necklace or other visible ejaculation. He talked to them extensively on camera so that both he and the viewer can come to know them before any sex scenes. Squirt pornography involves women ejaculating. The fetish centers around this fantasy portrayal. In the 1920s, Havelock Ellis reported that turn-of-the-century seamstresses using treadle-operated sewing machines could achieve orgasm by sitting near the edge milf fuck of their chairs. Group sex can occur hentai sex between people of all sexual orientations and genders. Especially popular in post-World War 2 Japanese culture. Such films continued to be produced but could only be distributed by underground channels.