Works in this genre may be considered adult for any number of reasons. The term is typically used by the cinematographer within the narrative framework of a pornographic film, and since the 1970s has become a leitmotif of the hardcore genre. A bisexual threesome may involve a man having sex with a man and a woman, the woman having sex with a man and a woman, or all three having sex with each other. Foot fetishism has been defined as a pronounced sexual interest in the feet or footwear. Bukkake is a sex act portrayed in pornographic films, in which several men ejaculate on a woman, or another man. Bondage websites and bondage imagery in mainstream pornography As of 2003, specialist bondage magazines were mostly displaced by the availability of bondage material on the World Wide Web, and the presence of bondage imagery in mainstream pornographic magazines such as Nugget and Hustler Taboo magazine. Point of view pornography is adult entertainment filmed to look as if the watcher were experiencing the sex act themselves. Yaoi is anime or manga that features gay males . It has since mature milfs become popular enough with couples to be discussed during an episode gay boy porn of Sex and the City. The activity is done by itself or as a part of or prelude hentai movies to other activities which many times involve sex. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Arcane or occult pornography involves sexualized situations with an occult or magical tone or performers who costume themselves in keeping with the theme, for example, a male performer dressed as a wizard. Participants who exert sexual control over their partners are known as dominants or tops while participants who take the passive, receiving, or obedient role are known as submissives or bottoms. Behind the Green Door was one of the first pornographic films to feature sex between a white actress with a black actor . Clothed male, naked female is one-sided female nudity in which one or more females are nude while one or more men are clothed.