Pornographic films present sexual fantasies and usually include erotically stimulating material such as nudity. Sexologist Alfred Kind suggested that the buttocks is the primary sexual presentation site in primates. Mutual masturbation can be practiced by males or females in pairs or groups with or without actually touching another person as indicated by the following examples of contact versus non-contact scenarios: Non-contact mutual masturbation Two people masturbating in the presence of each other but not touching. Bottom and submissive are widely recognized terms for those partner in the relationship or activity who are, respectively, the physically receptive or controlled participants. A facial is a form of non-penetrative sex, though big tit milf it is generally performed after some other means of sexual stimulation, such as vaginal sex, anal sex, oral sex or masturbation. One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. In some societies, the terms fox, plum, chick, or chicken are preferred. Rough sex pornography is similar to pornography featuring sadomasochism, and typically features a Top who humiliates and/or degrades a Bottom while being physically violent towards them. In many cases, that person is also aroused by smelling body parts that have lesbian hentai a urine scent. Others may also use vibrators and other sexual devices more commonly associated with female masturbation. Bobbi gay twink porn S. The 1979 U. Emetophilia pornography involving vomiting and gagging. A sub-set of vaginal fisting attempts to photograph the female cervix immediately after the fist is removed from the now-gaping vagina. Enema pornography involves adults given enemas to others, often fake. Matsuo used amateur actresses in his videos, and he usually traveled to their hometowns for the filming. It may also involve touching, rubbing, or pinching the nipples or other erogenous zones while masturbating. Lesbian pornography made for women is usually made by women, and usually features women who identify as lesbian or bisexual.