The cover can have hinges or be a separate hot gay sex part. Clothed female, naked male pornography features naked men and clothed women; typically, the women humiliate and abuse the men or perform fellatio and/or handjobs on the men. However, various groups within society considered such depictions immoral, labelling them pornographic, and attempting to have them suppressed under obscenity laws, with varying degrees of success. The term comes from the French voyeur, one who looks. In contrast, a celebrity may take the route of openly releasing the tape and benefit directly from royalties as well as indirectly from the publicity. Behind the Green Door was one of the first pornographic films to feature sex between a white actress with a black actor . Its gain in prominence has been attributed to its depiction in the film Pecker, which was released in 1998. Bondage pornography specializes in the depiction of sexual bondage or BDSM activities as photographs, stories, movies, or drawings. In these research publications, it is suggested that real female ejaculation is the release of a very scanty, thick, and whitish fluid from the female prostate, while the squirting or gushing shown frequently in pornography is a different phenomenon, the expulsion of clear and abundant fluid, which has been shown to be a diluted fluid from the urinary bladder. New York photographer Irving Klaw also published illustrated adventure/bondage hentai movies serials by fetish artists Eric Stanton, Gene Bilbrew, Adolfo Ruiz and others. Some people masturbate by using machines that simulate intercourse. Reality and voyeur pornography, animated videos, and legally prohibited acts also influence the classification of pornography. Studies have found that masturbation is frequent momsex in humans of both sexes and all ages, although there is variation. In POV porn, the shooting style is generally similar to gonzo pornography, with the person receiving sexual gratification holding the camera him or herself—aiming it down at the actress or actor who is performing the sex act.