The existence of such content in commercially available pornography is widely considered an urban legend. Some anthropologists and sociobiologists believe that breast fetishism derives from the breasts similarity to buttocks, but instead provide sexual attraction from the front of the body. Clothed male, naked female is one-sided female nudity in which one or more females are nude while one or more men are clothed. Double penetration of the vagina, anus and mouth, can involve: Simultaneous penetration of the anus by two penises or other objects. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. Terminology for roles varies widely within the various BDSM subcultures. The term pearl necklace is used by some because the drops of semen deposited by the man resemble a necklace of translucent white pearls. Irrespective of the legal or social view of pornography, it has been used in a number of contexts. For some people, non-penetrative sex is the primary sexual activity hot gay sex of choice above all others. Other objects such as ball point pens and thermometers are sometimes used, although this practice can lead to injury and/or infection. New York photographer Irving Klaw also published illustrated adventure/bondage serials by fetish artists Eric Stanton, Gene Bilbrew, Adolfo Ruiz and others. 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. For circumcised males, on whom the glans is mostly or completely uncovered, this technique creates more direct contact between the hand and the glans. Reality and voyeur pornography, animated videos, and legally prohibited acts also influence the classification of pornography. Types of anal sex can also be a part hentai sex of lesbian sexual practices. The term BDSM dates milf fuck back to 1969; however, the origin of the term BDSM is unclear and is believed to have been formed either from joining the term B&D with S&M , or as a compound initialism from B&D, D&S , and S&M.