In Japanese, the term describes any type of perverse or bizarre sexual desire or act; it does not represent a genre of work. The glans itself may widen and lengthen as the stimulation continues, becoming slightly darker in colour, while the gliding action of the foreskin reduces friction. It is also followed by dedicated industry publications and trade groups as well as the mainstream press, private organizations , government agencies, and political organizations. These are often gay twink porn fake. Some pornographic films use an artificial semen substitute to simulate or enhance creampie shots. Preggo pornography features pregnant performers and may include erotic lactation as a fetish. Group sex pornography horny milfs features at least two men and two women , usually more, who all perform sex acts on each other. Patricia Hill Collins, an African-American writer, theorizes that this is derived from a stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result. Testosterone discourages fat storage in these areas. Most bisexual porn is made by small production companies rather than the major studios. If dramatic skills are naked celebrities not involved, a performer in a porn film may also be called a model. To avoid soreness from this resulting friction, some may prefer to use a personal lubricant, masturbation cream or saliva during masturbation. Crush pornography features objects being crushed by an actress or actor, who generally plays an overtly dominant role. Mammary intercourse is known as titty-fucking, titfuck, or a titjob in the United States, as well as tit wank or French fuck in the United Kingdom - the latter term dating back to the 1930s; while a more jocular equivalent is a trip down mammary lane. As a form of non-penetrative sex, it can be done for its own enjoyment or as foreplay. Barebacking usually refers to gay hentai a conscious and deliberate choice to forgo condoms. On the other hand, the masochist enjoys being hurt, humiliated, or hentai porno suffering within the consensual scenario.