Yaoi is anime or manga that features gay males . Cartoon pornography depicts illustrated or animated fictional characters in erotic videos gays and sexual situations. For some people, non-penetrative sex is the primary sexual activity of choice above all others. Certain websites have begun providing bondage videos and photographs featuring the kidnapping roleplay, which has been largely the hallmark of detective style bondage magazines. Ass to mouth is a slang term primarily used to describe the withdrawal of a penis from the receptive partner anus followed by the immediate insertion into the receptive partner mouth. The two sets of people involved often meet either randomly or arrange hentai videos to meet up beforehand over the Internet. This technique is also used by some men who are circumcised who have excess skin left from circumcision. Patricia Hill Collins, an African-American writer, theorizes that this is derived from a stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result. As a form of non-penetrative sex, it can be done for its own enjoyment or as foreplay. A study of 164 males in Finland from two SM clubs found that 18.2% had engaged in coprophilia; 3% as a sadist, 6.1% as a masochist, and 9.1% as both. 18% of heterosexuals and 17% of homosexuals in the study pool had tried coprophilia, showing no statistically significant difference between heterosexuals and homosexuals. A 2009 study found that heterosexual male fat admirers preferred females that were clinically overweight and rated both lesbian milfs overweight and obese women more positively than slighter individuals. To avoid soreness from this resulting friction, some may prefer to use a personal lubricant, masturbation cream or saliva during masturbation. Mammary intercourse is known as titty-fucking, titfuck, or a titjob in the United States, as well as tit wank or French fuck in the United Kingdom - the latter term dating back to the 1930s; while a more jocular equivalent is a trip down mammary lane.