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. The original definition of dogging – and which is still a closely related activity – is spying on couples having sex in a car or other public place. Pussing: British expression for an activity involving a consenting couple where the male partner watches the woman urinate otherwise undetected in a semi-public place, usually a toilet cubicle at a pub, hotel, restaurant, theatre/cinema, office, club etc. If dramatic skills are not involved, a performer in a porn film may also be called a model. It is sometimes combined with BDSM features. Examples of heterosexual pornographic film series featuring creampies include Cream Filled Teens and Internal Cumbustion. It is typically animated pornography, as the legal age gay bear porn to be featured in a pornographic film in Japan is 18. 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. Multiple men and women Bisexual pornography features hentai movies one woman and two men who all perform sex acts on each other. Use of the agreed safeword is seen by some as an explicit withdrawal of consent. A pornographic work is characterized as hardcore if it has any hardcore content, no matter how small. Barebacking usually refers to a conscious and deliberate choice to forgo condoms. Participants who exert sexual control over their partners are known as dominants milf xxx or tops while participants who take the passive, receiving, or obedient role are known as submissives or bottoms. Since the 1980s, many practitioners and organizations have adopted the motto safe, sane and consensual, commonly abbreviated as SSC, which means that everything is based on safe activities, that all participants be of sufficiently sound/sane mind to consent, and that all participants do consent. When the interest in a particular subject is obsessive, the behavior may be described as stalking.