Performers are usually clean-shaven, thinner and more effeminate than ones in mainstream gay pornography. Mutual masturbation can be practiced by males or females in pairs or groups with or without actually touching another person as indicated by the following examples of contact versus non-contact scenarios: Non-contact mutual masturbation Two people masturbating in the presence of each other but not touching. This may help them develop their orgasm, increase its pleasure, and may inspire them to masturbate on a more frequent basis. Pornography may be presented in a variety of media, including books, magazines, postcards, photographs, sculpture, drawing, painting, animation, sound recording, film, video, and video games. BDSM actions can often take place during a specific period of time agreed to by both parties, referred to as play, a scene or a session. Currently, hentai sex animated television series aimed at adults are some of the most popular and critically acclaimed forms of entertainment. It is used, for example, at fertility clinics to stimulate sperm donors. The wife who enjoys cuckolding her husband is frequently called a hotwife, or a cuckoldress if the man is more submissive. The concept of lesbian, to differentiate women with a shared sexual orientation, is a 20th-century construct. In human sexuality, a threesome is sexual activity that involves three people at the same time. Related genres include: Amateur pornography originally referred only to pornography produced by amateurs but now also includes professionally naked milf made pornography designed to appear as if it were amateur. Even though the performers who perform in these films typically appear on many reality hot gay sex websites within a short span of time, most of these websites claim that each of them is an amateur. This may relate to fetishes such as voyeurism or cuckolding. 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.