Works in this genre may be considered adult for any number of reasons. Biological anthropologist Helen B. For circumcised males, on whom the glans is mostly or completely uncovered, this technique creates more direct contact between the hand and the glans. Such ejaculation can be done by mammary intercourse, or masturbation over the other person, or result from the withdrawal of the penis from a partner mouth as he is ejaculating gay twinks following fellatio, irrumatio, or intercourse. Bukkake is a sex act portrayed in pornographic films, in which several men ejaculate on nude milfs a woman, or another man. Women who perform in lesbian celebrity nudes pornography often do not consider themselves lesbian or bisexual. Specific sex acts Anal Anal pornography features anal penetration with a penis, dildo, other objects, or some combination of them. Incest itself is largely taboo, and is a crime in many countries. 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. If one person is penetrated by two objects, it is generically called double penetration . Use of the agreed safeword is seen by some as an explicit withdrawal of consent. Many cultures describe pain as an aphrodisiac. 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. Irrespective of the legal or social view of pornography, it has been used in a number of contexts. Snowballing or snowdropping is the human sexual practice in which one person takes someone else semen into his or her mouth and then passes it to the mouth of the other, usually through kissing. Macrophilia is a fascination with or a sexual fantasy involving giants, more hentai porn naked celebrities commonly expressed as giantesses . Bestiality is illegal in many countries.