Explicit sexual activity, such as sexual penetration, may occur within a session, but is not essential. In D/S, the Dominant is the Top and the submissive is the Bottom. Sometimes, asymmetric and often intentionally uncomfortable positions are employed to heighten the psychological impact of the bondage. Teabagging is the act of placing one testicles on another face or in their mouth. Though the term anal sex most commonly means penile-anal penetration, sources sometimes use the term anal intercourse to refer exclusively to penile-anal penetration, and anal sex to refer to any form of anal sexual activity, especially between pairings as opposed to anal masturbation. Spanking or whipping pornography involves spanking or whipping, generally of the buttocks, with the hand or with other objects such as belts, switches, paddles, brushes, or whips. Interracial pornography typically employs ethnic and racial stereotypes in its depiction of performers and many of interracial pornographic films still include racial stereotypes, although the segregation of actors by race has diminished considerably. Yuri is the lesbian equivalent. Lesbians may encounter distinct physical or mental health concerns arising from discrimination, prejudice, and minority stress. Cum shots have become the object of fetish genres like bukkake. One is in a vertical side of the box for the neck of the person who has their head inside the smotherbox. This is not due to a medical need. Scenes of multiple penetration gay movies are common in pornography. In terms of physical pleasure, a woman genitals may get direct stimulation from the base of the dildo, or in lesbian milfs the case of a double-ended dildo, from vaginal penetration. When questioned about her particular kink Covét replied, If we women have to take it from behind, then why not a man? Bodily functions Menstrual or red rhapsody pornography features sexual activities involving women who are menstruating, hentai sex with a focus on the menstrual blood. Bukkake pornography usually depicts numerous men having sex with one woman, with multiple, usually 10 or more, men ejaculating on the female face.