The activity is done by itself or as a part of or prelude to other activities which many times involve sex. Gonzo pornography is a style of pornographic film that attempts to place the viewer directly into the scene. The queening stool is also related to a smotherbox, which also allows the person under the seat to be locked in place, restrained by the neck as in a set of stocks. A scene where many women have sex with one man is referred to celebrities sex video as a reverse gang-bang. The term has origins in the Greek language . In the gay pornography industry, which uses amateurs as well as professional actors, the term gay-for-pay refers to actors labeled or believed to be straight but who engage in same-sex sexual activities for money. The loose and direct camera work often includes tight shots of the genitalia, unlike some traditional porn. The volume of semen that is ejaculated depends on several factors, including the male health, age, degree of sexual excitement, and the time since his last ejaculation. Production of such films was profitable, and a number of producers specialised in their production. This type of pornography is almost exclusively hentai, as true hermaphroditic humans are not fertile and are not usually found in nature. Some POV/gonzo porn sometimes breaks the strict point-of-view convention. See also Gay-for-pay. Some anthropologists and sociobiologists believe that breast fetishism derives from the breasts similarity to buttocks, but instead provide sexual attraction from the front of the body. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. The fantasy is typically based around one or more larger beings dominating a smaller being. The industry generally refers to such films as adult films, which is part of adult entertainment. In these research publications, it is suggested that real female ejaculation is the release of a very scanty, thick, and whitish fluid from the female prostate, while the squirting or gushing shown frequently in pornography is a different phenomenon, the expulsion of clear and abundant fluid, which has been shown to be a diluted fluid from the urinary bladder.