Perhaps following the example set by gay pornography, they have become a popular subgenre within heterosexual pornography since the turn of the century, featuring both vaginal and anal ejaculations. Contrary to the other two types, B/D does not define the Tops and Bottoms itself, and is used to describe the general activities with either partner being the receiver and the giver. Often other friends and community members may witness the signing of such a document in a ceremony, and so parties violating their agreement can result in loss of face, respect or status with their friends in the community. The industry generally refers to such videos porno gay films as adult films, which is part of adult entertainment. Following World War II, during a period of social repression when governments actively persecuted homosexuals, women developed networks to socialize with and educate each other. Yaoi is anime or manga that features gay males . Pornography may fall into more than one genre. The strategies and tactics that are used to smuggle one of the couple into and out of the toilet undetected are as important or almost as important as the urination. Being forced to wear diapers as a form of humiliation is sometimes a behavior encountered in sexual masochism. A study of the condom usage habits of New Zealand sex workers said that they offered various safe sex alternatives to vaginal sex to clients who refused to wear a condom. At the gay hentai end of the evening the female partners would randomly select keys from the bowl and leave with that key owner. Gay pornography is the representation of sexual activity between males. Preggo pornography features pregnant performers and may include erotic lactation as a fetish. Pussing: British expression for an activity involving a consenting couple where the male partner watches the woman urinate otherwise undetected in a semi-public place, usually a toilet cubicle at a pub, hotel, restaurant, theatre/cinema, office, club etc. Commenting on why there are not as many female macrophiles, psychologist Helen Friedman theorized that because women in most societies already view men as dominant and powerful, there no need for them to fantasize momsex about it.