The most successful animated features produced in the United States primarily for adult audiences were directed by Ralph Bakshi, including Fritz the Cat, Heavy Traffic and Coonskin. No causal relationship is known between masturbation and any form of mental or physical disorder. People may experience pleasure from anal sex by stimulation of the anal nerve endings, and orgasm may be achieved through anal penetration – by indirect stimulation of the prostate in men, indirect clitoral/G-spot stimulation in women, and associated sensory nerves . This type of pornography is almost exclusively mature milfs hentai, as true hermaphroditic humans are not fertile gay twink porn and are not usually found in nature. Most bisexual porn is made by small production companies rather than the major studios. The term BDSM dates back to 1969; however, the origin of the term BDSM is unclear and is believed to have been formed either from joining the term B&D with S&M , or as a compound initialism from B&D, D&S , and S&M. Mutual masturbation foreplay The manual stimulation of each other genitals where the session eventually leads to sexual intercourse. Group sex pornography features at least two men and two women , usually more, who all perform sex acts on each gay hentai other. In these research publications, it is suggested that real female ejaculation is the release of a very scanty, thick, and whitish fluid from the female prostate, while the squirting or gushing shown frequently in pornography is a different phenomenon, the expulsion of clear and abundant fluid, which has been shown to be a diluted fluid from the urinary bladder. However, gay pornography in the modern world is mostly concentrated in the making of home videos , cable broadcast and emerging video on demand and wireless markets, as well as images and movies for viewing on the Internet. Macrophilia is a fascination with or a sexual fantasy involving giants, more commonly expressed as giantesses . Mutual masturbation, mutual manual stimulation of the genitals between partners, can be a substitute for sexual penetration.