Female-to-male strap-on pornography became a popular sub-genre in the United States in the early 21st century, with a number of studios producing dedicated series about it. POV pornography involves camera angles designed to provide the viewer a view similar to that seen by one of the participants, whose face is never shown. Bestiality pornography involves the sexual attraction of humans to animals. Typically features a feminine Uke, or submissive, and a masculine Seme, or dominative. The other is in the top of the box to expose their face. The most established and probably most cliché set form of dominance and submission is Dominance and slavery. After the prerequisite level of sexual stimulation has been achieved, and ejaculation becomes imminent, the male will position his penis so that the semen discharged will be deposited onto his partner face. This type of censoring also extends to comics, video games, and anime made for adults. Felching involves drinking recently ejaculated semen from the vagina or anus. It gay sex videos explores the more mental aspect of BDSM. In recent years, Japanese films of this genre have become more common in the USA and Europe although it still remains a small, fetish-oriented part of the adult film industry. In a separate article analyzing 12 men who engaged in bestiality, an additional analysis of an 11-man subgroup revealed that 6 had engaged in coprophilic behavior, compared with only 1 in the matched control group consisting of 12 SM-oriented males who did not engage in bestiality. It has been described as professionally made porn which seeks to emulate the style of amateur pornography. The fundamental principles for the exercise of BDSM require that it should be performed with the informed consent of all involved parties. Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. They may repeat this cycle multiple times.