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. Use of the agreed safeword is seen by some as an explicit withdrawal of consent. In S/M, the Sadist is usually the Top and the Masochist the Bottom, but these roles are frequently more complicated or jumbled momsex . Many cultures describe pain as gay twinks an aphrodisiac. The phrase buttered bun is sometimes used to refer to the owner of the orifice in question. 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. The term Asiaphile is sometimes used to describe the same phenomenon as is yellow fever . There has been an increase in discussion and portrayal of masturbation in art, popular music, television, films, and literature. Fisher said that perhaps, the fleshy, rounded buttocks attracted males during rear-entry intercourse. Animal masturbation has been observed in many species, both in the wild and in captivity. Men may also rub or massage the glans, the rim of the glans, hentai porn and the frenular delta. Interactive pornography, available in CD-ROM and DVD format, allows the viewer to select the particular acts performed at any one time, sometimes with the camera providing a first person view. This can, however, redirect semen into the bladder . It is also known colloquially as gushing or squirting, although these are considered to be different phenomena in some research publications. Some women who engage in same-sex sexual activity may reject not only identifying as lesbians but as bisexual as well, while other women self-identification as lesbian may not align with their sexual orientation or sexual behavior; sexual identity is not necessarily the same as one sexual orientation or sexual behavior, due to various reasons, such as the fear of identifying their sexual orientation in a homophobic setting.