Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. As with most forms of sexual activity, anal sex participants risk contracting sexually transmitted infections . Clothed female, naked male is a genre of erotica featuring one or more nude men and one or more clothed women. Arguably the most famous example of the genre is the Taboo series. There are currently no known laws forbidding the crushing of objects and insects, however the production or trade of crush erotica involving live vertebrates is condemned by animal rights activists and is illegal in many countries, including the United States and Great Britain. The term is a slang word that originated in the gay community and comes from the equestrian term bareback, which refers to the practice of riding a horse without a saddle. Fantasies of group sex are extremely common among both men and women, and group sex is a subgenre in pornographic films. However the genre remains a very small proportion of the pornographic DVD market; for example at porn retailer HotMovies. Futanari, Hentai females with a penis. After the prerequisite level of sexual big tit milf stimulation has been achieved, and ejaculation becomes imminent, the male will position his 3d hentai penis so that the semen discharged will be deposited onto his partner face. Twink pornography features younger performers, and usually features young men under 30 who identify as gay or bisexual. Jail/Prison/Police pornography involves people in police custody hot gay sex or inmates in jails or prisons in various sexual situations, such as strip searches or body cavity searches. The principal characteristic of voyeurism is that the voyeur does not normally interact directly with the subject of his/her interest, who is often unaware of being observed. Sexual scenarios may involve male domination, female submission, exhibitionism and erotic entertainment.