Group sex can occur between people of all sexual orientations and genders. One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. Pornography is generally classified as either softcore or hardcore pornography. Such films continued to be produced but could only be distributed by underground channels. It is mutual consent that makes a clear legal and ethical distinction between BDSM and such crimes lesbian milfs as sexual assault or domestic violence. In September 2003 the BBC reported on the new dogging craze. Voyeurism: Seeing another urinate without the person knowledge either through video taping by a hidden camera, or by lurking in locations where people are urinating or are likely to have an urge to urinate. It may involve sexual attraction to women who are pregnant or appear pregnant, attraction to lactation, or attraction to particular stages of pregnancy such as impregnation or childbirth. Incest pornography can feature actual relatives, but the main type of this pornography simply uses actors of similar looks to suggest family relationship. Related genres include: Amateur pornography originally referred only to pornography produced by amateurs but now also includes professionally made pornography designed to appear as if it were amateur. 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. However, the tradition of bondage magazines continues in the form of art books of bondage photographs, published by mainstream publishers such as Taschen. The first film was released in 1980 starring hentai porn Kay Parker. 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.