Others may also use vibrators and other sexual devices more commonly associated with female masturbation. While most tentacle erotica is animated, there are also a few live-action movies. Interracial pornography typically employs ethnic and racial stereotypes in its depiction gay hentai of performers and many of interracial pornographic films still include racial stereotypes, although the segregation of actors by race has diminished considerably. Freud, however, considered such extensions of sexual interest to fall within the range of the normal, unless marked out by exclusivity . Human urinal: An act common in the bondage sex community where a male or female slave will serve as a urinal for a dominant partner. There is also some evidence that pornography can be used to treat voyeurism. Within a BDSM or D/s context, facesitting can be an especially intense form of erotic humiliation. The fundamental principles for the exercise of BDSM require that it should be performed with the informed consent of all involved parties. Especially popular in post-World War 2 Japanese culture. As observation is encouraged, voyeurism and exhibitionism gay bear porn are closely associated with dogging. It may be regarded as taboo or unnatural, and is a criminal offense in some countries, punishable by corporal or capital punishment; by contrast, people also regard anal sex as a natural and valid form of sexual activity that may be as equally fulfilling as any other desired sexual expression. Rough sex pornography is similar to pornography featuring sadomasochism, and typically features a Top who humiliates and/or big tit milf degrades a Bottom while being physically violent towards them. The first pegging scene appears to have been in the non-pornographic 1970 film Myra Breckinridge, based on the novel of the same name by Gore Vidal, although it was not explicit. Bukkake videos are a relatively prevalent niche in contemporary pornographic films. Initially, few animation studios in the United States attempted to produce animation for adult audiences, but later examples of animation produced for adults would gain mainstream attention and success.