Such films continued to be produced but could only be distributed by underground channels. Boot fetishism is a sexual fetish dedicated to boots. However, the tradition of bondage magazines continues in the form of art books of bondage photographs, published by mainstream publishers such as Taschen. 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. Saliva pornography involves salivation and saliva. The buttocks in human females thus contain more adipose tissue than videos gays in males, especially after puberty. Performers are usually clean-shaven, thinner and more effeminate than ones in mainstream gay pornography. Bukkake, Gokkun, Omorashi, and tentacle erotica are few uniquely Japanese genres known to western viewers. This technique may include the use of a simulacrum, or artificial vagina. This may relate to fetishes such as voyeurism 3d hentai or cuckolding. The prostate gland is one of the organs that contributes fluid to semen. Pegging is a sexual practice in which a woman performs anal sex on a man by penetrating the man anus with a strap-on dildo. It may be used as foreplay, or as an alternative to sexual penetration. It is commonly depicted in pornography, but very rarely in mainstream cinema. Lesbianism has been a theme in erotic art since at least the time of ancient Rome, and many regard depictions of lesbianism to be erotic. Internal ejaculations, followed by images of semen dripping from the anus, are sometimes depicted in bareback gay pornography, where they are referred to by the term breeding or the reverse money shot. Clothes wetting: The person is sexually aroused by wetting one clothing or observing another person doing so. Sub-genres of Japanese porn Among the various sub-genres of Japanese pornography are the following: Lolicon ロリコン: This genre involves prepubescent momporn and adolescent girls between the aged of 6-12.