Penetration may involve use of fingers, toes, sex toys, or penises. Such grounds and even the definition of pornography have differed in various historical, cultural, and national contexts. Particularly, some pornography in this genre features butch women, who are almost never seen in mainstream pornography. The slave is usually strictly forbidden from placing their lips directly on the body of the dominant so the practice routinely involves them receiving much of the spray all over their face, hair and body, however, another way of doing this that applies mostly to male dominants, is to place the mouth on the head of the penis and drink the urine as it is released. Female masturbation involves the stroking or rubbing of a woman vulva, especially her clitoris, with an index or middle fingers, or both. The genre presents itself as real couples having real sex. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. Unlike the usual power neutral relationships and play styles commonly followed by couples, activities and relationships within a BDSM context are often characterized by the participants taking on complementary, but unequal roles; thus, the idea of informed consent of both the partners becomes essential. The allusion is to the use of hemp rope for restraining prisoners, as a symbol of power, in the same way that stocks or manacles are used in a Western BDSM context. A spanking may be carried out with the use of a bare or gloved hand, or with any of a variety of implements, including a paddle, strap, hairbrush, feather duster or belt. It has since become popular enough with couples to be discussed during an episode of Sex and the gay twinks City. In contrast, a celebrity may take the route of openly releasing mature milfs the tape and benefit directly from royalties as well as indirectly from the publicity. In recent years, however, gay hentai many celebrities have benefited from the publicity resulting from the release of a sex tape.