The most common type of erotic spanking is administered on the bare buttocks, but can also be combined with bondage, in order to heighten sexual arousal and feelings of helplessness. Some pornographic films use an artificial semen substitute to simulate or enhance creampie shots. 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. The most common male masturbation technique is simply to hold the penis with a loose fist and then to move the hand up and down the shaft. Sexual relations between lesbian milfs women have been illustrated as well as narrated, but much of the written material from the early modern period has been destroyed. Content featuring male bisexuality has been a growing trend since the advent of internet pornography. Participants who exert sexual control over their partners are known as dominants or tops while participants who take the passive, receiving, or obedient role are known as submissives or bottoms. Boots are seen as the perhaps most fetishistic of all footwear and boots may be the most popular fetish clothing attire. Bestiality is illegal in many countries. It has since become popular enough with couples gay cock to be discussed during an episode of Sex and the City. 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. Cum shots typically do not appear in girl-girl scenes and orgasm is normally implied by utterances, cinematic conventions, or body movement. Double penetration of the vagina, anus and mouth, can involve: Simultaneous penetration of the anus by two penises or other objects. Many fantasies include the macrophile shrinking before a normal sized woman or keeping his or her normal height while the partner grows in size. On May 27, 2010 the television program The Doctors discussed the topic with dozens of teens, anime hentai parents, and professionals.