Anti-pornography psychologist Ana Bridges and colleagues conducted a content analysis of best-selling heterosexual pornographic videos showing that over 96% of all scenes concluded with a male performer ejaculating onto the body of his female partner. However, gay movies sex researchers and adolescent health care professionals have found no evidence for the existence of rainbow parties, and as such attribute the spread of the stories to a moral panic. For example, the Kama Sutra, in particular, goes into specific detail on how to properly strike a partner during sex. The stimulation may involve hands, fingers, everyday objects, sex toys or combinations of these. The legal status of masturbation has also varied through history and masturbation in public is illegal in most countries. For their consent, they must have relevant information at hand and the necessary mental capacity to judge. Caro rejected that as being a necessary conclusion, stating that female fatty deposits on the hips improve individual fitness of the female, milf fuck regardless of sexual selection. Bukkake videos are a relatively prevalent niche in contemporary pornographic films. The essence of voyeurism is the observing but may also involve the making of a secret photograph or video of the subject during an intimate activity. 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. The pornography is geared towards men; hence the word bisexual refers to the men rather than the woman. As with most forms of sexual activity, anal sex participants risk contracting sexually transmitted infections . Arguably the most famous example of the genre is the Taboo series. It can be combined with fellatio and the woman may move her breasts up and down on the penis for an additional stimulation, usually before the man reaches orgasm. Am Abend , one lesbian hentai of the earliest pornographic films that have been collected at the Kinsey Institute for Research in Sex, Gender, and Reproduction, starts with a female masturbation scene.