Starting with erotic stories and woodblock prints from before the 20th century, Japanese pornography evolved into distinct subcategories with the media that in addition of pornographic videos and magazines featuring live actors, there is exist categories of pornographic manga , pornographic computer games , and pornographic anime . Portrayals of lesbians in the media suggest that society at large has been simultaneously intrigued and threatened by women who challenge feminine gender roles, momsex and fascinated and appalled with women who are romantically involved with other women. Internal ejaculation shots are a comparatively recent development in pornography; they are not found in early pornographic films. There has been an increase in discussion and portrayal of masturbation in art, popular music, television, films, and literature. Diaper fetishism is totally independent from pedophilia as the wearer derives pleasure only from the diaper and/or use of it. Female lesbian hentai dominance refers to BDSM relationships and BDSM scenes in which the dominant partner is female. The term applies to the depiction of the act rather than the act itself, and so does not include live exhibitions like sex shows and striptease. The original definition of dogging – and which is still a closely related activity – is spying on couples having sex in a car or other public place. This industry employs thousands of performers along with support and production staff. A survey by the New York City Department of Health and Mental Hygiene found that heterosexual women are more likely to bareback when engaging in anal sex than homosexual and bisexual men. Group sex most commonly takes place in a private sex party or semi-public swinger gathering, but may also take place at massage parlors or brothels or, in some jurisdictions, at purpose-built locations such as sex clubs. John Stagliano is considered to have started the gonzo pornography gay twink porn genre with his Buttman series of films. Solo performances in gay pornography have been described in 1985 as either or both active and/or passive , whereas female solo performances are said to be exclusively passive .