The term sadomasochism is derived from the words sadism and masochism . Sexologist Alfred Kind suggested that the buttocks is the primary sexual presentation site in primates. Examples of mentally oriented practices are education games, during which the dominant requires certain forms of behavior from the submissive. Throughout history, women have not had the same freedom or independence to pursue homosexual relationships as men, but neither have they met the same harsh punishment mature milfs as homosexual men in some societies. Ass to mouth pornography shows the transfer of a performer penis from a second performer anus to that same second performer mouth in a single shot. Rainbow parties were covered on The Oprah Winfrey Show in 2003, and became the subject of a juvenile novel called Rainbow Party. Incest itself is largely taboo, and is a crime in many countries. Terminology for roles varies widely within the various BDSM subcultures. Interactive 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. Sadomasochism is practiced in isolation relatively rarely, though some masochists report biting, pinching, or even stun-gunning themselves as a prelude to, or as part of, masturbation. Mammary intercourse is a sex act, performed as foreplay or as non-penetrative sex, that involves the stimulation of the male penis by the female breasts and vice versa. Double Stuffed , Double Vaginal , or Double gay cock Anal pornography involves the hentai movies penetration of one orifice by two penises or other objects. Stimulating the prostate from outside, via pressure on the perineum, can be pleasurable as well. Lolita pornography features women who are 18 years old or slightly older, who pretend to be underage teen girls. Irrespective of the legal or social view of pornography, it has been used in a number of contexts. The genres of pornography are based on the type of activity featured and the category of participants, for example mateur pornography is a category of pornography that features models, actors or non-professionals performing without pay, or actors for whom this material is their only paid modeling work.