Rape pornography features performers simulating hentai porn rape. Interracial pornographic films have experienced an explosion in popularity, becoming one of the fastest-growing and biggest-selling genres. Often, strong views are expressed with regard to anal sex; it is controversial in various cultures, especially with regard to religion, commonly due to prohibitions against anal sex among gay men or teachings about the procreative purpose of sexual activity. Terminology for roles varies widely within the various BDSM subcultures. Real medical shots or videos may violate privacy laws in some countries. Gay-for-pay describes male or female actors, pornographic stars, or sex workers who self-identify as heterosexual but who are paid to act or perform as homosexual professionally. The porn industry and viewing public were shocked by the then-taboo spectacle of a white woman having sex with a black man. Foot fetish pornography features heavy emphasis on the feet of the participants, either in combination with kissing and genital sex or in the context of acts such as trampling or crush fetishism. Hamedori is a genre of Japanese pornography in which a male adult video actor or director serves as the camera operator. A variant of A2M is ATOM milf xxx where a performer inserts his penis directly from one recipient anus into a second recipient mouth. Transsexual pornography is a genre of pornography. In the fetish cuckolding subculture, it is most common for the female to take on the sexually dominant role and the male the submissive role, however, female subs, sometimes referred to as cuckqueans, also exist. The term Asiaphile is sometimes used to describe hot gay sex the same phenomenon as is yellow fever . Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. As of 2013, little analysis of this paraphilia has been reported in medical literature.