A variation on this is to place the fingers and thumb on the penis as if playing a flute, and then shuttle them back and forth. Since at least 1973, it has also been used to refer to a sexually attractive young woman. Well-known female porn stars who expressed their pleasure in pegging their male partners include Taylor Wane, Debi Diamond, Brittany Andrews, and Monique Covét. Shibari is a Japanese word that literally means to tie or to bind. Ethnic pornography is a genre of pornography that features performers of specific ethnic groups, or depictions of interracial sexual activity. Emetophilia pornography involving vomiting and gagging. Can also include auto-fellatio, or performing oral sex on oneself. The term hentai is never used in this context in Japanese. Pornography is generally classified as either softcore or hardcore pornography. Bisexual DVDs sell much better online than in adult video stores, possibly due to customers in stores feeling embarrassed to buy them. Male masturbation may differ between males who have been circumcised and those videos gays who have not. It like associating every Christian with the zealots who cause religious wars. Depictions of male and female masturbation are common in pornography, including gay pornography. When he is in porn milf position the cover is closed. Voyeurism: Seeing another urinate without the person knowledge either through video taping by a hidden camera, or by lurking in locations where people are urinating or are likely to have an urge to urinate. There is also some evidence that pornography can be used to treat voyeurism. Bisexual pornography is a genre of pornography which most typically depicts one woman and two men who all perform sex acts on each other. Mammary intercourse is said by Alex Comfort to produce mutual orgasm in women with sensitive breasts , and it was one of the nine substitute exercises for penetrative sexual activities, as hentai videos detailed in the Paradis Charnels of 1903. Interracial pornography typically employs ethnic and racial stereotypes in its depiction of performers and many of interracial pornographic films still include racial stereotypes, although the segregation of actors by race has diminished considerably.