The term pearl necklace is used by some because the drops of semen deposited by the man resemble a necklace of translucent white pearls. Diaper pornography involves performers wearing diapers, sometimes with an adult performer acting in the role of a caretaker. Evolutionary psychologists suggest that rounded buttocks may have evolved horny milfs to be desirable trait because they provide a visual indication of the woman youth and fertility. Since mammary intercourse is a non-penetrative sex act, the risk of passing a sexually transmitted infection that requires direct contact between the mucous membranes and pre-ejaculate or semen is greatly reduced. Although there may be no connection between coprophilia and sadomasochism , the limited data lesbian hentai on the former comes from studies of the latter. On May 27, 2010 the television program The Doctors gay sex video discussed the topic with dozens of teens, parents, and professionals. Pornography is often distinguished from erotica, which consists of the portrayal of sexuality with high-art aspirations, focusing also on feelings and emotions, while pornography involves the depiction of acts in a sensational manner, with the entire focus on the physical act, so as to arouse quick intense reactions. A survey by the New York City Department of Health and Mental Hygiene found that heterosexual women are more likely to bareback when engaging in anal sex than homosexual and bisexual men. Double Stuffed , Double Vaginal , or Double Anal pornography involves the penetration of one orifice by two penises or other objects. Bear features a combination of middle-aged, hairy or overweight males. 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. Tentacle erotica can be consensual, but frequently contains elements of non-consensual sex. For example, in Australia it is rated Refused Classification . Arcane or occult pornography involves sexualized situations with an occult or magical tone or performers who costume themselves in keeping with the theme, for example, a male performer dressed as a wizard.