Works in this genre may be considered adult for any number of reasons. Bukkake anime hentai pornography involves a performer, usually female, onto whom several men young gay porn or women ejaculate, usually on the face. Women with women Main mature milfs article: Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. The resulting consent and understanding is occasionally summarized in a written contract, which is an agreement of what can and cannot take place. 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. Interactive pornography, available in CD-ROM and DVD format, allows the viewer to select the particular acts performed at any one time, sometimes with the camera providing a first person view. Snowballing or snowdropping is the human sexual practice in which one person takes someone else semen into his or her mouth and then passes it to the mouth of the other, usually through kissing. Such ejaculation can be done by mammary intercourse, or masturbation over the other person, or result from the withdrawal of the penis from a partner mouth as he is ejaculating following fellatio, irrumatio, or intercourse. Behind the Green Door was one of the first pornographic films to feature sex between a white actress with a black actor . There are various subcultures under this umbrella term and distinct difference between these subcultures. Yaoi is anime or manga that features gay males . Such works have also often been subject to censorship and other legal restraints to publication, display or possession. A scene where many women have sex with one man is referred to as a reverse gang-bang. Barebacking usually refers to a conscious and deliberate choice to forgo condoms. The current public acceptance of celebrities with sex tapes is speculated by Joe Levy, executive editor of Rolling Stone, to be due to the easy availability of pornography, as well as couples more commonly making their own tapes due to the prevalence of video cameras.