Yaoi is anime or manga that features gay males . Most bisexual porn is made by small production companies rather than the major studios. Those with diaper-related paraphilias differ widely in their focus of attention. As a form of non-penetrative sex, it can be done for its own enjoyment or as foreplay. Bondage pornography specializes in the depiction of sexual bondage or BDSM activities as photographs, stories, movies, or drawings. It is also followed by dedicated industry publications and trade groups as well as the mainstream press, private organizations , government agencies, and political organizations. The Silent Duck, also called Duck-Billing, is the technique often used in which the person engaging in hand insertion shapes the hand to resemble a duck beak. Common phrases used to refer to these individuals are chicks with dicks or the derogatory term shemale, hentai porn although these are generally considered pejorative among transwomen. At the end of the evening the female partners would randomly select keys from the bowl and leave with that key owner. Multiple men and women Bisexual gaysex pornography features one woman and two men who all perform sex acts on each other. Macrophilia is a fascination with or a sexual fantasy involving giants, more commonly expressed as giantesses . Some pornographic films use an artificial semen substitute to simulate or enhance creampie shots. Pornography may fall into more than one genre. Hermaphrodite, also known as herm, refers to pornography, typically hentai, that features persons with the genitalia of both sexes. Patricia Hill Collins, an African-American writer, theorizes that this is derived from a stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result. A pornographic big tit milf work is characterized as hardcore if it has any hardcore content, no matter how small. Sexual relations between women have been illustrated as well as narrated, but much of the written material from the early modern period has been destroyed.