In the 1970s, the hardcore pornography genre introduced the stereotypical momporn cumshot scene as a central element of the hardcore film, in which the male actor ejaculates in a way ensuring maximum visibility of the act itself. Fisting may be performed with or without a partner. Cartoon Network has dedicated a late night programming block to adult animation, known as Adult Swim. An orgy is a gathering where guests freely engage in open and unrestrained sexual activity or group sex; and a bunga bunga orgy is an orgy in which participants have sex underwater, such as in a swimming pool or a hot tub. One-sided male nudity can also arise when a male disrobes as part of a male striptease. The legal status of masturbation has also varied through history and masturbation in public is illegal in most countries. Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. Masturbation has been depicted in art since prehistoric times and is mentioned and discussed in very early writings. Fantasies of group sex are extremely common among both men and women, and group sex is a subgenre in pornographic films. It is distinguished from these concepts in that the cuckold thrill in their partner acts is specifically masochistic; as such it is considered a category of BDSM fetish. The meaning of hentai is perversion, abnormality, or metamorphosis. It generally contains nudity or partial nudity in sexually suggestive situations. For other scenes, particularly in established relationships, gay movies a safeword may be agreed to signify a warning rather than explicit withdrawal of consent; and a few choose not to use a safeword at all. Actors are mostly amateur; any well-known actors in bisexual porn tend to be from anime hentai the gay pornography industry. It may involve sexual attraction to women who are pregnant or appear pregnant, attraction to lactation, or attraction to particular stages of pregnancy such as impregnation or childbirth.