This stop and go build-up, known as edging, can achieve even stronger orgasms. 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. Some restrict a policy of panties/nipple tape for females and some allow full nudity with explicit sexual interaction allowed. The smotherbox nude milfs is placed on a stable surface. Pornography is often referred to as porn and a pornographic work as a porno. Animal masturbation has been observed in many species, both in the wild and in captivity. Simultaneous penetration of the mouth and either the vagina or anus. Softcore anime hentai gay pornography also exists; it at one time constituted the genre, and may be produced as beefcake pornography for heterosexual female and homosexual male consumption. The stigma of being gay or labeled as such has steadily eroded since the Stonewall riots began the modern American gay rights movement in 1969. There may be more than two participants; both group sex and gang banging can be included. It is commonly gay movies depicted in pornography, but very rarely in mainstream cinema. The current record is held by Lisa Sparks who had sex with 919 men on October 16, 2004 in Warsaw, Poland as part of the Third Annual World Gangbang Championship and Eroticon 2004. Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. Babysitter pornography features usually teenage girls being exploited and having taboo sex with older, male employers. Hamedori is a genre of Japanese pornography in which a male adult video actor or director serves as the camera operator. Hentai is the various forms of Japanese pornography, including H-manga, H-anime, and H-computer games. A female dominant in a master/slave relationship is often termed a Mistress, not to be confused with the colloquial usage of mistress as a kept sexual partner without a similarly formalized power relationship.