Although there may be no connection between coprophilia and sadomasochism , the limited data on the former comes from studies of the latter. The primary subjects of pornographic depictions are pornographic models, who pose for still photographs, and pornographic actors or porn stars, who perform in pornographic films. Such documents have not been recognized as being legally binding, nor are they intended to be. Many times a top actor will then be sought as a bottom and the debut is often treated as a black gay porn notable event or even its own release. It has since become popular enough with couples to be discussed during an episode of Sex and the City. Swinging can take place in various contexts, ranging from a spontaneous sexual activity at an informal social gathering of friends to a regular social gathering in a sex club or residence. No causal relationship is known between masturbation and any form of mental or physical disorder. The term breast fetishism is also used to refer to cultural attention to female breasts and the sexuality they represent, with debate continuing as to whether the modern widespread fascination with breasts among heterosexual males in western societies is a sexual fetish. Locks may be used to emphasize the submissive position or the submissive hands may be fastened above his head to the box. Works in this genre may explore philosophical, political or social issues. The mouth was the most common area to be ejaculated upon. While wearing diapers, a diaper fetishist generally experiences a comforting feeling. Felching is a sexual practice involving the act of orally sucking semen out of the vagina or anus of one partner. The activity is done by itself or as a part of or prelude to other activities which many times involve sex. These styles are much closer to the style of bondage scenes in mainstream television. The slave is usually strictly forbidden from placing their lips directly on the body of the dominant so the practice routinely involves them receiving much of the spray all over their face, hair and body, however, another way of doing this that applies mostly to male dominants, is to place the mouth on the head of the penis and drink the urine as it is released.