Group sex pornography features at least two men and two women , usually more, who all perform sex acts on each other. The niche popularity grew significantly in the latter half of the first decade of the 2000s. To avoid soreness from this resulting friction, some may prefer to use a personal lubricant, masturbation cream or saliva during masturbation. Medical pornography involves sexualized medical, often fake, gay twinks including gynecological pelvic examinations, rectal examinations, and pelvic or gynecological ultrasounds. The name was coined from the title of the controversial book. Some prefer a particular type of clothing to urinate. Diaper fetishism, nappy fetishism or diaperism, is a sexual fetish in which a person feels a desire to wear or use diapers. Such works have also often been subject to censorship and other legal restraints to publication, display or possession. Among swinging couples, one of the two partners is often the driving force and the other is more passive-supportive of the addition of additional sex parties. Breeding is sometimes followed by felching, which involves sucking anime hentai the semen from the lesbian milfs partner anus. The resulting consent and understanding is occasionally summarized in a written contract, which is an agreement of what can and cannot take place. Lolita pornography caters to ephebophiles. Behind the Green Door was one of the first pornographic films to feature sex between a white actress with a black actor . HIV is among the infections that require such direct contact and is therefore very unlikely to be transmitted via mammary intercourse. In POV porn, the shooting style is generally similar to gonzo pornography, with the person receiving sexual gratification holding the camera him or herself—aiming it down at the actress or actor who is performing the sex act. Gay pornography is the representation of sexual activity between males. While some fantasize about a giantess who is slightly taller than himself, others are interested in giantesses that are hundreds or even thousands of feet tall.