Bukkake pornography involves a performer, usually female, onto whom several men or women ejaculate, usually on the face. Lesbian pornography typically features a wider range of appearances and body types than is typical of mainstream pornography. Femdom features BDSM scenes in which the dominant partner is female. Buttocks are sometimes emphasized in pornography, where they are often referred to as booty. Some pornographic films use an artificial semen substitute to simulate or enhance creampie shots. The most common type of erotic spanking is administered hentai sex on the bare buttocks, but can also be combined with bondage, in order to heighten sexual arousal and feelings of helplessness. Real school shots or videos which are sexualized may violate privacy laws in some countries. Masturbation is the self-sexual stimulation of the genitals for sexual arousal or other sexual pleasure, usually to the point of orgasm. His most famous model was Bettie Page, who became the first celebrity of bondage film and photography. Interactive gay bear porn pornography, available in CD-ROM and DVD format, allows the viewer to select the particular acts performed at any one time, sometimes with the camera providing a first person view. A woman can use a secondary vibrator, between the dildo and her genitals, to get pleasure from pegging. The term BDSM dates back to 1969; however, the origin of the term BDSM is unclear and is believed to have been formed either from joining the term B&D with S&M , or as a compound initialism from B&D, D&S , and S&M. In humans, females generally have more round and voluptuous buttocks, caused by estrogen that encourages the body to store fat in the buttocks, hips, and thighs. Hermaphrodite, also known as herm, refers to pornography, typically hentai, that features persons milf fuck with the genitalia of both sexes. Standing up, a chair, the corner of an item of furniture, or even a washing machine can be used to stimulate the clitoris through the labia and clothing. The term bondage describes the practice of Physical restraining.