Mammary intercourse is a sex act, performed as foreplay or as non-penetrative sex, that involves the stimulation of the male penis by the female breasts and vice versa. It is also known colloquially as gushing or squirting, although these are considered to be different phenomena in some research publications. A study of 164 males in Finland from two SM clubs found that 18.2% had engaged in coprophilia; 3% as a sadist, 6.1% as a masochist, and 9.1% as both. 18% of heterosexuals and 17% of homosexuals in the study pool had tried coprophilia, showing no statistically significant difference between heterosexuals and homosexuals. Common positions include lying on back or face down, sitting, squatting, kneeling or standing. The act may be carried out face to face, or head to tail, with the woman recommended to be on top if she has smaller breasts. Foot fetishism has been defined as a pronounced sexual interest in mature milfs the feet or footwear. The volume of semen that is ejaculated depends on several factors, gay black including the male health, age, degree of sexual excitement, and the time since his last ejaculation. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. New York photographer Irving Klaw also published illustrated adventure/bondage serials by fetish artists Eric Stanton, Gene Bilbrew, Adolfo Ruiz and others. 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. 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 hentai porn back to the 1930s; while a more jocular equivalent is a trip down mammary porn cartoon lane. Women oriented pornography gay twinks is sometimes referred to as sex positive pornography. Medical pornography best mobile porn involves sexualized medical, often fake, including gynecological pelvic examinations, rectal examinations, and pelvic or gynecological ultrasounds.