Another variant of reality pornography consists of normal couples that are filmed by professionals, in which case the only obvious distinction from amateur pornography is the higher quality of production, filming and editing. Unlike erotic films, pornographic films contain explicit sexuality and do not claim any artistic merit. Real jail or prison or police station shots or videos may violate laws in some gay cock countries. Saliva pornography involves salivation and saliva. It can be combined with fellatio and the woman may move her breasts up and down on the penis for an additional stimulation, usually before the man reaches orgasm. While bondage is a very popular variation within the larger field of BDSM, it is nevertheless sometimes differentiated from the rest of this field. Reality Reality pornography refers to real or faked amateur encounters. Pornographic momporn films are generally classified into sub-genres which describe the sexual fantasy which the film and actors attempt to create. In the context of consensual erotic activities, sadism and masochism are not strictly accurate terms; there is a significant difference from the medical or psychological usage of both terms. The stimulation may involve hands, fingers, everyday objects, sex toys or combinations of these. It may be used as foreplay, or as anime hentai an alternative to sexual penetration. Especially popular in post-World War 2 Japanese culture. In gay pornographic movies, actors who identify themselves as heterosexual, but who nevertheless perform explicit sexual acts with other males on film do not face the same stigmas as the mainstream acting counterparts and indeed can rise quickly to being featured actors. The sub-genres usually conform to certain conventions, and each may appeal to a particular audience. The first film was released in 1980 starring Kay Parker. While most tentacle erotica is animated, there are also a few live-action movies. Though the term anal sex most commonly means penile-anal penetration, sources sometimes use the term anal intercourse to refer exclusively to penile-anal penetration, and anal sex to refer to any form of anal sexual activity, especially between pairings as opposed to anal masturbation.