The term hentai is never used in this context in Japanese. A variant of A2M is ATOM where a performer inserts his penis directly from one recipient anus into a second recipient mouth. Some restrict a policy of panties/nipple tape for females and some allow full nudity with explicit sexual interaction allowed. It is commonly depicted in pornography, but very rarely in mainstream cinema. The name of the practice, when it is done in a repeated in-and-out motion, is derived from its passing resemblance to the dipping of a tea bag into a cup of hot water as a method of brewing tea. Squirt pornography gay sex video involves women ejaculating. Within a BDSM or D/s context, facesitting can be an especially intense form of erotic humiliation. Individuals who can change between top/dominant and bottom/submissive roles—whether from relationship to relationship or within a given relationship—are known as switches, though the term switch in this context is occasionally seen as derogatory and is rejected by many who might simplistically fit the definition. The term lesbian is also used with regard to sexual identity or sexual behavior, regardless of sexual orientation, or as an adjective to characterize or associate nouns with female homosexuality or same-sex attraction. The term is a slang word that originated horny milfs in the gay community and comes from the equestrian term bareback, which refers to the practice of riding a horse without a saddle. Unlike erotic films, pornographic films contain explicit sexuality and do not claim any artistic merit. Incest pornography can feature actual relatives, but the main type of this pornography simply uses hentai sex actors of similar looks to suggest family relationship. The term soft crush refers to the more common fetish surrounding videos involving inanimate objects or small invertebrates being crushed, while the term hard crush refers to such videos involving larger animals with vertabrae, and arguably more pain-susceptible animals . Depictions of male and female masturbation are common in pornography, including gay pornography.