Terminology for roles varies widely within the various BDSM subcultures. Examples of heterosexual pornographic film series featuring creampies include gay cock Cream Filled Teens and Internal Cumbustion. The porn industry and viewing public were shocked by the then-taboo spectacle of a white woman having sex with a black man. In more vigorous forms of fisting, such as punching or punchfisting, a fully clenched fist may be inserted and withdrawn slowly. As a result, little in history was documented to give an accurate description of how female homosexuality is expressed. It has also been recommended as a form of foreplay or safer sex. Transgender pornography features performers who cross-dress for sexual gratification, either for themselves or for their partners. Bottom and submissive are widely recognized terms for those partner in the relationship or activity who are, respectively, the physically receptive or controlled participants. The scenario is a genre of erotica, which on the internet is sometimes abbreviated to CMNF, and may involve sexual and nonsexual erotic scenarios. The person receiving anilingus is regarded as the passive partner in the act, and the person performing anilingus is the active partner. Voyeurism: Seeing another urinate without the person knowledge either through video taping by a hidden camera, or by lurking in locations where people are urinating or are likely to have an urge to urinate. Mammary intercourse is said by Alex Comfort to produce mutual orgasm in women with sensitive breasts , and it was one of the nine substitute exercises for penetrative sexual activities, as detailed in the Paradis Charnels of 1903. It is commonly depicted in pornography, momporn but very rarely in mainstream cinema. Men may find stimulation gay hentai of the anus, rectum, and adjacent organs enjoyable. Omorashi: The act of holding one own urine until the need to urinate is urgent, making another hold in their urine, or watching another person with an urgent need to urinate. Female ejaculation is the expulsion of fluid by the paraurethral ducts through and around the human female urethra during or before an orgasm.