Bisexual pornography is a genre of pornography which most typically depicts one woman and two men who all perform sex acts on each other. 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. Strictly speaking, gay fuck bondage means binding the partner by tying their appendages together; for example, by the use of handcuffs or by lashing their arms to an object. Watersports pornography features sexual activities involving urine, such as golden showers. Especially popular in post-World War 2 Japanese culture. Insertion in pornography features women inserting various odd objects into their anus or vaginas. 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. Some techniques which may work for one individual can be difficult or uncomfortable for another. Saliva pornography involves salivation and saliva. Bukkake, Gokkun, Omorashi, lesbian hentai and tentacle erotica are few uniquely Japanese genres known to western viewers. Big Beautiful Woman is a euphemism for an overweight woman and is frequently used in the context of fat fetishism. A female dominant in a master/slave relationship is often termed a Mistress, not to be confused with the colloquial usage of mistress as a kept sexual partner without a similarly formalized power relationship. Now facial cumshots are regularly portrayed in pornographic films, videos, magazines and internet web sites. Actual upskirt or downblouse shots may big tit milf violate privacy laws in some countries. Mammary intercourse is said by Alex Comfort to produce mutual orgasm in women with sensitive breasts , and it was one of the nine substitute exercises for penetrative sexual activities, as detailed in the Paradis Charnels of 1903.