Rubber pornography involves rubber, latex, and similar materials. A 2009 study found that heterosexual male fat admirers preferred females that were clinically overweight and rated both overweight and obese women more positively than slighter individuals. Some may pursue fantasies that are concerned with the circumstances in which a subject may give birth, or to the conditions to which the pregnant subject may find themselves acting upon, such as approaches to mobility, sleeping, and dressing. 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. Cartoon pornography depicts illustrated or animated fictional characters in erotic and sexual situations. Following World War II, during a period of social repression when governments actively persecuted homosexuals, women developed networks to socialize with and educate each other. Among fetishists, the pose of reluctance—the victimization of the cuckold—is a major element of the paraphilia. It therefore has the connotation of being wild, dangerous, gay boy porn and fun. Some consider the act to be as simple as fellatio involving the scrotum. It is typically animated pornography, as the legal age to be featured in a pornographic film in Japan is 18. It is also referred to as anal–oral contact and anal–oral sex, or colloquially as rimming or a rim job, momsex and may be performed by or on people of any sexual orientation for personal pleasure or as a form of erotic humiliation. In general, as compared to conventional relationships, BDSM participants go to great lengths to negotiate the important aspects of their relationships in advance, and to take great care in learning about and following safe practices. Some are aroused from wetting their diapers, others like messing their diapers. Lesbianism in erotica deals with depictions in the visual arts of lesbianism, which is the expression of female-to-female hentai sex sexuality.