Snuff pornography involves the actual death of any of the participants, consenting or otherwise, simulated death is not considered snuff. In the context of consensual erotic activities, sadism and masochism are not strictly accurate terms; there is a significant difference from the medical or psychological usage of both terms. Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, hentai porn explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. Transsexual porn star Wendy Williams has stated that transsexual porn is classified as Straight Specialty. Group sex lesbian milfs is sexual behavior involving more than two participants. Gloryhole pornography features women performing fellatio on unidentified men through a small hole made in a bathroom divider. As with most forms of sexual activity, anal sex participants risk contracting sexually transmitted infections . Cum-shot pornography features a collection of male ejaculation scenes. Male masturbation may differ between males who have been circumcised and those who have not. Partners can engage in penetrative sex, known as full swap, or choose to soft swap in which they engage only in non-penetrative sex. In some areas, there are laws stating it is not legally possible to consent to be killed, and elsewhere it may still be legally dubious . Greater economic and social freedom allowed them gradually to be able to determine how they could form relationships gay twink porn and families. The name of the practice, when it is done in a repeated in-and-out motion, is derived from its passing resemblance to the dipping of a tea bag into a cup of hot water as a method of brewing tea. Pornographic films present sexual fantasies and usually include erotically stimulating material such as nudity.