This category also includes pornographic home movies. Lesbianism has been a theme in erotic art since at least gay movies the time of ancient Rome, and many regard depictions of lesbianism to be erotic. Now facial cumshots are regularly portrayed in pornographic films, hentai sex videos, magazines and internet web sites. By Japanese law, the genitals of actors and actresses must be censored and up the mid-1990 so was the depiction of pubic hair. Celebrity sex tapes are amateur or professionally-made recordings of sex acts, as performed by a celebrity and their partner. It may be used as foreplay, or as an alternative to sexual penetration. Bottom and submissive are widely recognized terms for those partner in the relationship or activity who are, respectively, the physically receptive or controlled participants. Incest pornography can feature actual relatives, but the main type of this pornography simply uses actors of similar looks to suggest family relationship. BDSM actions can often take place during a specific period of time agreed to by both parties, referred to as play, a scene or a session. Sexologist Alfred Kind suggested that the buttocks is the primary sexual presentation site in primates. 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. In academic discourse, racial fetishism is a postcolonialist term found in the writings of authors such as Homi K. Adult animation is genre of animation geared towards adults and sometimes teens. Internal ejaculations, followed by images momporn of semen dripping from the anus, are sometimes depicted in bareback gay pornography, where they are referred to by the term breeding or the reverse money shot. Kinbaku means tight binding Kinbaku-bi which literally means the beauty of tight binding.