Can also include auto-fellatio, or performing oral sex on oneself. Jail/Prison/Police pornography involves people in police custody or inmates in jails or prisons in various sexual situations, such as strip searches or body cavity searches. In places where non-monogamous sex is taboo or illegal, group sex may take place in private or clandestine locations including homes, hotel rooms, or private clubs. In a separate article analyzing 12 men who engaged in bestiality, an additional analysis of an 11-man subgroup revealed that 6 had engaged in coprophilic behavior, compared with only 1 in the matched control group consisting of 12 SM-oriented males who did not engage in bestiality. Some productions are noted for sophisticated and/or experimental gay bear porn storytelling and animation techniques. 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 of their chairs. Interest in BDSM can range from one-time experimentation to a lifestyle. Fisting may be performed with or without a partner. Sexual scenarios may involve male domination, hentai videos female submission, exhibitionism and erotic entertainment. Unlike Yaoi, Bara is normally made by actual homosexual men, for homosexual men, and tends to focus on the more realistic obstacles and challenges that come with being homosexual in Japan. This is commonly called double anal or double stuffing. 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. Social attitudes towards the discussion and presentation of sexuality has become more tolerant and legal definitions of obscenity have become more limited, leading to an industry for the production and consumption of pornography in the latter half of the 20th century. In straight pornography, intercourse is often followed by a facial, pearl necklace or other visible ejaculation. Erotic spanking is the act of spanking another person for the sexual arousal or gratification of either or both parties.