Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography gay cock Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. The purpose of this kind of agreement is primarily to encourage discussion and negotiation in advance, and then to document that understanding for the benefit of all parties. Many of these activities might be based on rape. Some people masturbate by using machines that simulate intercourse. A smotherbox gives a more dramatic experience . Studies among BDSM practitioners in the US have shown that about half of all men find the idea of bondage to be erotic; many women porn milf do as well. Positions can also be chosen specifically for added effects such as increased humiliation, elevation and suspension. Cartoon pornography includes, hentai videos but is not limited to, hentai and parody renditions of famous cartoons and comics. Some POV/gonzo porn sometimes breaks the strict point-of-view convention. The cover is open while the submissive lies down on his back and places his head in the box. Many times a top actor will then be sought as a bottom and the debut is often treated as a notable event or even its own release. Activities range from a spontaneous smack on bare buttocks during a sexual activity, to occasional sexual roleplay, such as ageplay, to domestic discipline and may involve the use of a hand or the use of a variety of spanking implements, such as a spanking paddle or cane. 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. Works in this genre may explore philosophical, political or social issues. Among fetishists, the pose of reluctance—the victimization of the cuckold—is a major element of the paraphilia. This technique is also used by some men who are circumcised who have excess skin left from circumcision. A threesome is also depicted with one woman and two men who all perform sex acts on each other .