Portrayals of lesbians in the media suggest that society at large has been simultaneously intrigued and threatened by women who challenge feminine gender roles, and fascinated and appalled with women who are romantically involved with other women. John Stagliano is considered horny milfs to have started the gonzo pornography genre with his Buttman series of films. The term BDSM dates back to 1969; however, the origin of the term BDSM is unclear and is believed to have been formed either from joining the term B&D with S&M , or as a compound initialism from B&D, D&S , and S&M. Perhaps following the example set by gay pornography, they have become a popular subgenre within heterosexual pornography since the turn of the century, featuring both vaginal and anal ejaculations. Urolagnia is a form of salirophilia in which sexual excitement is associated with the sight or thought of urine or urination. Sub-genres can also be classified into the characteristics of the performers or the type of sexual activity on which it concentrates, and not necessarily on the market to which each sub-genre appeals. This is commonly called videos gays double vaginal penetration or double stuffing. Today, pornographic films can be sold or rented on DVD, shown through Internet and special channels and pay-per-view on cable and satellite, and in adult theaters. 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. Older names for a pornographic film include stag film, and blue movie. The term is typically used by the cinematographer hentai sex within the narrative framework of a pornographic film, and since the 1970s has become a leitmotif of the hardcore genre. Rainbow parties were covered on The Oprah Winfrey Show in 2003, and became the subject of a juvenile novel called Rainbow Party. At the end of the evening the female partners would randomly select keys from the bowl and leave with that key owner.