In Japanese, the term describes any type of perverse or bizarre sexual desire or act; it does not represent a genre of work. Some masturbate only using pressure applied to the clitoris without direct contact, for example by pressing the palm or ball of the hand against underwear or other clothing. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. As a form of non-penetrative sex, it can be naked milf done for its own enjoyment or as foreplay. In the West, masturbation in private or with a partner is generally considered a normal and healthy part of sexual enjoyment. Sexual orientation Pornography features an increasing variety of combinations of actors by their sexual orientation such as lesbian, gay, bisexual, and transsexuals in addition to traditional heterosexual roles. The existence of such content in commercially available pornography is widely considered an urban legend. If dramatic skills are not involved, a performer in a porn film may also be called a model. For 3d hentai example, in Australia it is rated Refused Classification . This genre also features male-on-male fellatio through a small hole made in a bathroom divider. Use of the agreed safeword is seen by some as gay bear porn an explicit withdrawal of consent. Hardcore pornography is pornography that depicts penetration or extreme fetish acts, or both. In Japan, point of view pornography is referred to as hamedori . In S/M, the Sadist is usually the Top and the Masochist the Bottom, but these roles are frequently more complicated or jumbled . The phrase buttered bun is sometimes used to refer to the owner of the orifice in question. The cover can have hinges or be a separate part. The niche popularity grew significantly in the latter half of the first decade of the 2000s. Though there have been numerous gang bang pornographic films since the 1980s, they usually involved no more than half a dozen to a dozen men. Internationally, hentai is a catch-all term to describe a genre of anime and manga pornography.