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. Another variant of reality pornography consists of normal couples that are filmed by professionals, in which case the only obvious distinction from amateur pornography nude milfs is the higher quality of production, filming and editing. It is also often mixed with other fetishes in practice, such as voyeurism, denial, etc. In addition to mainstream pornography, the popularity of facials has led to creation of its own niche market, like video series that specialize in showing the act. Each participant may engage in any type of sex acts with one or both of the others, such as vaginal, anal or oral sex or mutual masturbation. Partners can engage in penetrative sex, known as full swap, or choose to soft swap in which they engage only in non-penetrative sex. Matsuo used amateur actresses in his videos, and he usually traveled to their hometowns for the filming. It is sometimes described as a sexual fantasy, by women or men, gay twinks depicting an exhibitionist or physique worship scenario. 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. Such films continued to be produced but could only be distributed by underground channels. Some do not hentai movies use the diapers at all, for arousal, or bladder and bowel movements. Mutual masturbation can be practiced by males or females in pairs or groups with or without actually touching another person as indicated by the following examples of contact versus non-contact scenarios: Non-contact mutual masturbation Two people masturbating in the presence of each other but not touching. Foot fetishism, foot partialism, foot worship, or podophilia is a pronounced sexual interest in feet.