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. The 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. Pornography may fall into more than one genre. There is, however, no third party camera work involved. Animal masturbation has been observed in many species, both in the wild and in captivity. Barebacking usually refers to a conscious and deliberate choice to forgo condoms. The range of its individual characteristics is thereby wide. Though there have been numerous gang bang pornographic films since the 1980s, they usually involved no more than half a dozen to a dozen men. The porn industry and viewing public were shocked by the then-taboo spectacle of a white woman having sex with a black man. It is also followed by dedicated industry publications and trade groups as well as the mainstream press, private organizations , government agencies, and political organizations. Several hundred exclusively pegging films were produced, as well as twice as many bisexual and straight films with strap-on scenes. Usually that person prefers to stage the wetting so that his/her legs become soaked with urine. Multiple men and women Bisexual pornography features one woman and two men who all perform sex acts on each other. Solo performances in gay pornography have been described in 1985 as either or both active and/or passive , whereas female solo performances are said to be exclusively passive . The reverse of this, in which nude women interact with clothed men, is called Clothed male, naked young gay porn female . A few extremely flexible males can reach and stimulate their penis 3d hentai with their tongue milf fuck or lips, and so perform autofellatio.