Threesome can also refer to a love triangle, a three-way romantic relationship. Solo performances in gay pornography have been described in 1985 as either or both active and/or passive , whereas female solo performances are said to be exclusively passive . Mammary intercourse is a sex act, performed as foreplay or as non-penetrative sex, that involves the stimulation of the male penis by the female breasts and vice versa. Starting with erotic stories and woodblock prints from before the 20th century, Japanese pornography evolved into distinct subcategories with the media that in addition of pornographic videos and magazines featuring live actors, there is exist categories of pornographic manga , pornographic computer games , and pornographic anime . 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. What seems clear from the historical record is that much of the lesbian material in pornographic texts was intended for a male readership. The porn industry and viewing public were shocked by the then-taboo spectacle of a white woman having sex with a black man. Diaper pornography involves performers wearing diapers, sometimes with an adult performer acting in the role of a caretaker. Some straight actors have started acting in gay porn only to be accused of being gay while others first step was to strictly do solo scenes. The term applies to the depiction of the act rather than the act itself, and so does not include live exhibitions like sex shows and striptease. It is geared towards heterosexual men, who most typically define a threesome as such. Participants who exert sexual control over their partners are known as dominants or tops while participants who take hentai porn the passive, receiving, or obedient role are known as submissives or bottoms. However, bisexual pornography is often placed near the gay section in adult video stores, since many consumers are gay men. Mammary intercourse is known as titty-fucking, titfuck, momporn or a titjob gay twink porn in the United States, as well as tit wank or French fuck in the United Kingdom - the latter term dating back to the 1930s; while a more jocular equivalent is a trip down mammary lane.