Common positions include lying on back or face down, sitting, squatting, kneeling or standing. Medical pornography involves sexualized medical, often fake, including gynecological pelvic examinations, big tit milf rectal examinations, and pelvic or gynecological ultrasounds. When used as an alternative to penile-vaginal penetration, the goal may be to preserve virginity or to prevent pregnancy. It has since become popular enough with couples to be discussed during an episode of Sex and the City. The term has origins in the Greek language . Certain websites have begun providing bondage videos and photographs featuring the kidnapping roleplay, which has been gay boy porn largely the hallmark of detective style bondage magazines. Bukkake is a sex act portrayed in pornographic films, in which several men ejaculate on a woman, or another man. New York photographer Irving Klaw also published illustrated adventure/bondage serials by fetish artists Eric Stanton, Gene Bilbrew, Adolfo Ruiz and others. 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. Ass to mouth is a slang term primarily used to describe the withdrawal of a penis from the receptive partner anus followed by the immediate insertion into the receptive partner mouth. However, various groups within society considered such depictions immoral, labelling them pornographic, and attempting to have them suppressed under obscenity laws, with varying degrees of success. Use of the agreed safeword is seen by some as an anime hentai explicit withdrawal of consent. Yaoi is anime or manga that features gay males . 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.