The essence of voyeurism is the observing but may also involve the making of a secret photograph or video of the subject during an intimate activity. The anus has a relatively high concentration of nerve endings and can be an erogenous zone, and the receiver may receive pleasure from external anal stimulation. Some BDSM practitioners prefer a code of behavior that differs from SSC and is described as risk aware consensual kink , indicating a preference for a style in which the individual responsibility of the involved parties is emphasized more strongly, with each participant being responsible for his or her own well-being. In some societies, the terms fox, plum, chick, or chicken are preferred. It may be used as foreplay, or as an alternative to sexual penetration. A common way that these are depicted in a hentai videos single scene is with one woman and two men performing together. The fundamental principles for the exercise of BDSM require big tit milf that it should be performed with the informed consent of all involved parties. Ethnic pornography is a genre of pornography that features performers of specific ethnic groups, or depictions gay boy porn of interracial sexual activity. Masturbation has been depicted in art since prehistoric times and is mentioned and discussed in very early writings. The effect is to give the viewer the sense that they are experiencing the sex acts that they are watching, as opposed to simply watching others as a voyeur. Body parts including fingers, tongue and penis may be used for anonymous oral, vaginal and/or anal intercourse. Using the term shemale for a transsexual woman often implies that she is working in the sex trade. Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. Going back at least as far as the Christy twins in the 1970s, depictions of incest and particularly incest between twins has been a feature of gay pornography.