Internal ejaculation shots are a comparatively recent development in pornography; they are not found in early pornographic films. Bondage/BDSM Bondage pornography features performers tied up or constrained in various ways. Normal quantities of ejaculate range from 1.5 to 5.0 milliliters . The term pearl necklace is used by some because the drops of semen deposited by the man resemble a necklace of translucent white pearls. A homosexual threesome would involve either hentai porn three men gaysex or three women. The concept of lesbian, to differentiate women with a shared sexual orientation, is a 20th-century construct. Rainbow party A rainbow party is an urban legend spread from the early 2000s. Tentacle erotica can be consensual, 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. Some anthropologists and sociobiologists believe that breast fetishism derives from the breasts similarity to buttocks, but instead provide sexual attraction from the front of the body. The phrase buttered bun is sometimes used to refer to the owner of the orifice in question. 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. On May 27, 2010 the television program The mature milfs Doctors discussed the topic with dozens of teens, parents, and professionals. The first explicit pegging scene is believed to have been in the 1975 pornographic film The Opening of Misty Beethoven. Hamedori is a genre of Japanese pornography in which a male adult video actor or director serves as the camera operator. The reverse of this, in which nude women interact with clothed men, is called Clothed male, naked female . Men may also rub or massage the glans, the rim of the glans, and the frenular delta. Transsexual pornography is a genre of pornography. For circumcised males, on whom the glans is mostly or completely uncovered, this technique creates more direct contact between the hand and the glans.