Contrary to the other two types, B/D does not define the Tops and Bottoms itself, and is used to describe the general activities with either partner being the receiver and the giver. Lying face down one may use the hands, one may straddle gay twinks a pillow, lesbian milfs the corner or edge of the bed, a partner leg or some scrunched-up clothing and hump the vulva and clitoris against it. Positions can also be chosen specifically for added effects such as increased humiliation, elevation and suspension. Shotacon : Similar to Lolicon, hentai movies this genre involves prepubescent or under-aged boys between the ages 6–12. A scene where many women have sex with one man is referred to as a reverse gang-bang. Studies have found that masturbation is frequent in humans of both sexes and all ages, although there is variation. 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. Lolita pornography features women who are 18 years old or slightly older, who pretend to be underage teen girls. Bondage pornography specializes in the depiction of sexual bondage or BDSM activities as photographs, stories, movies, or drawings. In Japan, point of view pornography is referred to as hamedori . The neologism pegging was popularized when it became the winning entry in a contest in Dan Savage Savage Love sex advice column, held after an observation was made that there was no common name for the act. Group sex most commonly takes place in a private sex party or semi-public swinger gathering, but may also take place at massage parlors or brothels or, in some jurisdictions, at purpose-built locations such as sex clubs. Lesbian pornography typically features a wider range of appearances and body types than is typical of mainstream pornography.