The naked celebrities most common type of erotic spanking is administered on the bare buttocks, but can also be combined with bondage, in order to heighten sexual arousal and feelings of helplessness. 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. Its gain in prominence has been attributed to its depiction in the film Pecker, which was released in 1998. 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. Double Stuffed , Double Vaginal , or Double Anal pornography involves the penetration of one orifice by two penises or other objects. A survey by the New York City Department of Health and Mental Hygiene found that heterosexual women are more likely to bareback when engaging in anal sex than homosexual and bisexual men. In Japanese, this natural-fibre rope is known as asanawa; the Japanese vocabulary does not make a distinction between hemp and jute. Sexual orientation Pornography features an increasing variety of combinations of actors by their sexual orientation such as lesbian, gay, bisexual, and transsexuals in addition to traditional heterosexual roles. John Stagliano is considered to have started the gonzo pornography genre with his Buttman hentai videos series of films. Adult animation is naked celebrities genre of animation geared towards adults and sometimes teens. Stimulating the prostate from outside, via pressure on the perineum, can be pleasurable as well. It is geared towards horny milfs heterosexual Black Porn men, who most typically define a threesome as such. Bestiality is illegal in many gay twinks countries. The term applies to the depiction of the act rather than the act itself, and so does gay male sex not include live exhibitions like sex shows and striptease. Types of anal sex can also be a part of lesbian sexual practices. Terminology for roles varies widely within the various BDSM subcultures. Spanking can be administered in a number of spanking positions.