Scenes of multiple penetration are common in pornography. In September 2003 the BBC reported on the new dogging craze. Central to the typical MILF narrative is an age-play dynamic of older women and younger lovers. It can also be heightened by the person saying that they have to urinate. Accepting that Eros is not always pretty, and may involve the forbidden or taboo - as with women pornography – forms part of the struggle with the good girl/bad girl or virgin-whore split in postmodern femininity. The nipples are erogenous zones, and vigorous stimulation of them during masturbation usually causes the penis to become erect more quickly than it would otherwise. Seconds after being deposited onto the face, the semen thickens, before liquefying 15–30 minutes later. Masturbation has been depicted momporn in art since prehistoric times and is mentioned and discussed in very early writings. Sexual scenarios may involve male domination, female submission, exhibitionism and erotic entertainment. Though the term anal sex most commonly means penile-anal penetration, sources sometimes use the term anal intercourse to refer exclusively to penile-anal penetration, and anal sex to refer to any form of anal sexual activity, especially between pairings as opposed to anal masturbation. Actors are mostly amateur; any well-known actors lesbian hentai in bisexual porn tend to be from the gay pornography industry. Spanking or whipping pornography involves spanking or whipping, generally of the buttocks, with the hand or with other objects such as belts, switches, paddles, brushes, or whips. Yaoi : Featuring two grown adult men in a homosexual/gay relationship. Voyeur or peeping Tom pornography is usually more staged with the subjects aware of the cameras, sometimes openly gaysex including this exhibitionist awareness. Fetish cuckolding can have a wide range of expression, from pillow-talk fantasy between monogamous partners to extreme alternative lifestyles, depending on the couple. Fantasies of group sex are extremely common among both men and women, and group sex is a subgenre in pornographic films.