It is commonly depicted in pornography, but very rarely in mainstream cinema. Bukkake, Gokkun, Omorashi, and tentacle erotica are few uniquely Japanese genres known to western young gay porn viewers. Crying pornography that features participating actors crying. 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. Guro or Gore is a genre of Japanese pornography involving blood, gore, disfiguration, violence, mutilation, urine, enemas, or feces. Bottom and submissive are widely recognized terms for those partner in the relationship or activity who are, respectively, the physically receptive or controlled participants. Such films continued to be produced but could only be distributed by underground channels. Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. The term discipline describes psychological restraining, with the use of rules and punishment to control overt behavior. A common way that these are depicted anime hentai in a single scene is with one woman momporn and two men performing together. Another variant of reality pornography consists of normal couples that are filmed by professionals, in which case the only obvious distinction from amateur pornography is the higher quality of production, filming and editing. A facial is a form of non-penetrative sex, though it is generally performed after some other means of sexual stimulation, such as vaginal sex, anal sex, oral sex or masturbation. Participants usually derive pleasure from this, even though many of the practices—such as inflicting pain or humiliation or being restrained—would be unpleasant under other circumstances. While bondage is a very popular variation within the larger field of BDSM, it is nevertheless sometimes differentiated from the rest of this field. Consent is the most important criterion here.