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. Clothed female, naked male is a genre of erotica featuring one or more nude men and one or more clothed women. 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 principal characteristic of voyeurism is that the voyeur does not normally interact directly with the subject of his/her interest, who is often unaware of being observed. 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. Fisting may be performed with or without a partner. A large part of the popularity of these videos is seeing how regular and normal the girls are in real-life. This is commonly called double anal or double stuffing. Pleasure for the giver during anilingus is usually based more on the principle of the act. The speed of the hand motion will vary from person to person, although it is not uncommon for the speed to increase as ejaculation nears and for it to decrease during the ejaculation itself. Some couples use a threesome as a way to develop a love triangle . Erotic spanking is the act of spanking another person for the sexual arousal or gratification of either or both parties. To tea bag is a slang term for the sexual act of a man placing his scrotum in the mouth of a willing sexual partner for pleasure or onto the face porno gay or head of another person. It is also often mixed with other fetishes in practice, such as voyeurism, denial, etc. Reality Reality pornography refers to real or faked amateur encounters. In many cases, that person is also aroused by smelling body parts that have a urine scent. The first pegging scene appears to have been in the non-pornographic 1970 film Myra Breckinridge, based on the novel of the same name by Gore Vidal, although it was not explicit.