Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. The anus has a relatively high concentration of nerve endings and can be an erogenous zone, and the receiver may receive pleasure from external anal stimulation. It is mutual consent that makes a clear legal and ethical distinction between BDSM and such crimes as sexual assault or domestic violence. Facial cum shots are currently regularly portrayed in pornographic films and videos, often as a way to close a scene. Clothed female, naked male is a genre of erotica featuring one or more nude men and one or more clothed women. English adopts and uses hentai as a genre of pornography by the commercial sale and marketing of explicit works under this label. They cited the Internet and text messaging as common ways of organising meetings. These agreements are binding in the sense that the parties have the expectation that the negotiated gay twink porn rules will be followed. A male voyeur is commonly labeled Peeping Tom, a term which originates from the Lady Godiva legend. Amateur porn has been called one porn milf of the most profitable and long-lasting genres of pornography. This technique may include the use of a simulacrum, or artificial vagina. Ass to mouth pornography shows the transfer of a performer penis from a second performer anus to that same second performer mouth in a single shot. Most soft crush hentai porn fetishists avoid being placed under the same label as hard crush fetishists, believing that crush films with larger animals give the entire group a bad label. Simultaneous penetration of the mouth and either the vagina or anus. Insertion in pornography features women inserting various odd objects into their anus or vaginas. Heterosexual bareback sex, as opposed to sex with condoms, not only poses an increased risk of STIs, but for pregnancy as well. It may be used as foreplay, or as an alternative to sexual penetration.