The term applies to the depiction of the act rather than the act itself, and so does not include live exhibitions like sex shows and striptease. 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. A sex party is a gathering at which sexual activity takes place. The work of Bruce Seven has been called reality porn, due to his lack of using scripts and asking his performers to act naturally in their own character. It has also been recommended as a form of foreplay or safer sex. Interracial pornographic films have experienced an explosion in popularity, becoming one of the fastest-growing and biggest-selling genres. The term combines nude milfs elements of the Freudian psychoanalytic fetish and the Marxist commodity fetish, and is used in the context of British, Spanish and French colonialism and imperialism and their aftereffects. For legal reasons, the vast majority of so-called reality porn involves professional actors and actresses posing young gay porn as so-called amateurs. Female ejaculation is the expulsion of fluid by the paraurethral ducts through and around the human female urethra during or before an orgasm. Transsexual porn star Wendy Williams has stated that transsexual Porn is classified as Straight Specialty. Stimulating the prostate from outside, via pressure on the perineum, can be pleasurable as well. Since the 1980s, many practitioners and organizations have adopted the motto safe, sane and consensual, commonly abbreviated as SSC, which means that everything is based on safe activities, that all participants be of sufficiently sound/sane mind to consent, and that all participants do consent. Lesbianism has been a theme in erotic art since at least the time of ancient Rome, and many regard depictions of lesbianism to be erotic. This fetish sometimes originates from childhood memories of needing, or of seeing another needing, to urinate. It is used, hentai sex for example, at fertility clinics to stimulate sperm donors.