A related term used in the genre is the term cougar, which implies an older woman as predator. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. Some anthropologists and sociobiologists believe that breast fetishism derives from the breasts similarity to buttocks, but instead provide sexual attraction from the front of the body. To avoid soreness from this resulting friction, some may prefer to use a personal lubricant, masturbation cream or saliva during masturbation. 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 phrase buttered hentai videos bun is sometimes used to refer to the mature milfs owner of the orifice in question. While anal sex is commonly associated with male homosexuality, research shows that not all gay males engage in anal sex and that it is not uncommon in heterosexual relationships. Reality and voyeur pornography, animated videos, and legally prohibited acts also influence the classification of pornography. HIV is among the infections that require such direct contact and is therefore very unlikely to be transmitted via mammary intercourse. In POV porn, the shooting style is generally similar to gonzo pornography, with the person receiving sexual gratification holding the camera him or herself—aiming it down at the actress or actor who is performing the sex act. In contrast, a celebrity may take the route of openly releasing the tape and benefit directly from royalties as well as indirectly from the publicity. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. Typically featured are hitting, choking, name-calling and hair-pulling. They may be noted for using hot gay sex risqué themes, graphic violence, sexuality or black comedy in a manner that is unsuitable for younger audiences.