Bondage/BDSM Bondage pornography features performers tied up or constrained in various ways. A pornographic work is characterized as hardcore if it has any hardcore content, no matter how small. Yuri hentai sex female homosexual hentai. Tentacle erotica can be consensual, momporn but frequently contains elements of non-consensual sex. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Solo performances in gay pornography have been described in 1985 as either or both active and/or passive , whereas female solo performances are said to be gay bear porn exclusively passive . Pornography in Japan is large and intertwined business of adult entertainment with unique characteristics that readily distinguish it from western pornography. Mammary intercourse is a sex act, performed as foreplay or as non-penetrative sex, that involves the stimulation of the male penis by the female breasts and vice versa. While anal sex is commonly associated with male homosexuality, research shows that not all gay males engage in anal sex and that it is not uncommon in heterosexual relationships. Spanking can be administered in a number of spanking positions. In Japanese, this natural-fibre rope is known as asanawa; the Japanese vocabulary does not make a distinction between hemp and jute. It is typically animated pornography, as the legal age to be featured in a pornographic film in Japan is 18. Voyeur pornography may also include shots of topless women on topless beaches who are unaware of the cameras but may legally be photographed due to the public setting. The phrase buttered bun is sometimes used to refer to the owner of the orifice in question. Interactive pornography, available in CD-ROM and DVD format, allows the viewer to select the particular acts performed at any one time, sometimes with the camera providing a first person view. In S/M, the Sadist is usually the Top and the Masochist the Bottom, but these roles are frequently more complicated or jumbled . Sigmund Freud considered foot binding as a form of fetishism.