Gay-for-pay describes male or female actors, pornographic stars, or sex workers who self-identify as heterosexual but who are paid to act or perform as homosexual professionally. It is also followed by dedicated industry publications and trade groups as well as the mainstream press, private organizations , government agencies, and political organizations. Solo pornography recognized with AVN Awards include hentai movies the All Alone series and All Natural: Glamour Solos. Jerk off instruction features a performer encouraging or instructing the viewer to masturbate, often culminating in a countdown at the end of which the viewer is invited to induce orgasm. Animal masturbation has been observed in many species, both in the wild and in captivity. 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. Double penetration of the vagina, anus and mouth, can involve: Simultaneous penetration of the anus by two penises or other objects. Evolutionary psychologists suggest that rounded buttocks may have evolved to be desirable trait because they provide a visual indication of the woman youth and fertility. Content featuring male bisexuality has been a growing trend since the advent of internet hot gay sex pornography. Examples include the Girls Gone Wild and Girls Who Like Girls Series. Usually th celebrity sex tapes at person prefers to stage the wetting so that his/her legs become soaked with urine. Fisher said that perhaps, the fleshy, rounded buttocks attracted males during rear-entry intercourse. Even though the performers who perform in these films typically appear on many reality websites within a short span of time, most of these websites claim that each of them is an amateur. A sex party is a gathering at which sexual activity takes place. If dramatic skills are not involved, a performer in big tit milf a porn film may also be called a model. The object or situation of interest is called hot gay sex the fetish; the person who has a fetish for that object/situation is a fetishist.