Am Abend , one of the earliest pornographic films that have been collected at the Kinsey Institute for Research in Sex, Gender, and Reproduction, starts with a female masturbation scene. The nipples are erogenous zones, and vigorous stimulation of them during masturbation usually causes the penis to become erect more quickly than it would otherwise. When questioned about her particular kink Covét replied, If we women have to take it from behind, then why not a man? Using the term shemale for a transsexual woman often implies that she is working in the sex trade. Technically this is a form of exhibitionism rather than group sex per se. Real enema shots or videos of true medical situations may violate privacy laws in some countries. Arguably the most famous example of the genre is the Taboo series. Unlike erotic films, pornographic films contain explicit sexuality and do not claim any artistic merit. See Gay-for-pay. Others may also use vibrators and other sexual devices more commonly associated with female masturbation. Bestiality pornography involves the sexual attraction of humans to animals. In the 1970s, the hardcore pornography genre introduced the stereotypical cumshot scene as a central element of the hardcore film, in which the male actor ejaculates in a way ensuring maximum visibility of the act itself. The fetish centers around this fantasy portrayal. The stimulation may involve hands, fingers, everyday objects, sex toys or combinations of these. The related term twinkle-toes, which implies that a man is effeminate, tends to be used in a derogatory manner. Pleasure for the giver gay twink porn during porn milf anilingus is usually based more on the principle of the act. These scenes may hentai sex either have the cameraman directly engaging in sex or merely filming others having sex. Body parts including fingers, tongue and penis may be used for anonymous oral, vaginal and/or anal intercourse. Bobbi S. This technique may include the use of a simulacrum, or artificial vagina. While most tentacle erotica is animated, there are also a few live-action movies.