Reflective of its views on sexuality and culture, Japanese pornography delves into a wide spectrum of heterosexual, homosexual, and transgender sexual acts in addition to unique fetishes and philias. One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. Such hentai sex films continued to be produced but could only be distributed by underground channels. The padding may also muffle noises from the outside, causing a relaxation effect and heightening their other senses. It may be used as foreplay, or as an alternative gay twink porn to sexual penetration. 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 term soft crush refers to the more common fetish surrounding videos involving inanimate objects or small invertebrates being crushed, while the term hard crush refers to such videos involving larger animals with vertabrae, and arguably more pain-susceptible animals . Squirt pornography involves women ejaculating. Generally, interest big tit milf differs between people, and gender depends on sexual orientation. Voyeurism: Seeing another urinate without the person knowledge either through video taping by a hidden camera, or by lurking in locations where people are urinating or are likely to have an urge to urinate. Going back at least as far as the Christy twins in the 1970s, depictions of incest and particularly incest between twins has been a feature of gay pornography. The term discipline describes psychological restraining, with the use of rules and punishment to control overt behavior. Bobbi S. Transsexual porn star Wendy Williams has stated that transsexual porn is classified as Straight Specialty. The rise of the Internet in the late 1990s and early 2000s similarly changed the way pornography film was distributed and furthermore complicated the censorship regimes around the world and the legal prosecution of obscenity.
