If one person is penetrated by two objects, it is generically nude milfs called double penetration . Adult animation is genre of animation geared towards adults and sometimes teens. Gay-for-pay describes male or female actors, pornographic stars, or sex workers who self-identify as heterosexual but who are paid to act or perform as homosexual professionally. Many fantasies include the macrophile shrinking before a normal sized woman or keeping his or her normal height while the partner grows in size. Sub-genres can also be classified into the characteristics of the performers or the type of sexual activity on which it concentrates, and not necessarily on the market to which each sub-genre appeals. The smotherbox is placed on a stable surface. The existence of such content in commercially available pornography is widely considered an urban legend. In general, BDSM play is usually structured such that it is possible for the consenting partner to withdraw his or her consent during a scene; for example, by using a safeword that was agreed on in advance. For much of the history of cinema and television, lesbianism was considered taboo, though since the 1960s it has increasingly become a genre in its own right. Many cultures describe pain as an aphrodisiac. Macrophilia is a fascination with or a sexual fantasy involving giants, more commonly expressed as giantesses . Some may keep their hand stationary while pumping into it with pelvic thrusts in order to simulate the motions of sexual intercourse. Transsexual porn star Wendy Williams has stated that transsexual Porn is classified as Straight Specialty. A few extremely flexible males can reach and stimulate their penis gay cock with their tongue or lips, and so perform autofellatio. For celebrity news circumcised males, on whom the glans is mostly or completely uncovered, this technique creates more hentai porn animated porn direct contact between the hand and the glans. Pornography is often distinguished from erotica, which consists of the portrayal of sexuality with high-art aspirations, focusing also on feelings and emotions, while pornography involves the depiction of acts in a sensational manner, with the entire focus on the physical act, so as to arouse quick intense reactions.