Multiple men lesbian milfs and women Bisexual pornography features one woman and two men who all perform sex acts on each other. Sometimes one or more fingers may be inserted into the vagina to stroke its frontal wall where the G-spot may be located. Biological anthropologist Helen B. The term bondage describes the practice of Physical restraining. Bukkake pornography involves a performer, usually female, onto whom several men or women ejaculate, usually on the face. In S/M, the Sadist is usually the Top and the Masochist the Bottom, but these roles are frequently more complicated or jumbled . Mammary intercourse is known as titty-fucking, titfuck, or a titjob in the United States, as well as tit wank or French fuck in the United Kingdom - the latter term dating back to the 1930s; while a more jocular equivalent is a trip down mammary lane. Such ejaculation can be done by mammary intercourse, or masturbation over the other person, or result from the withdrawal of the penis from a partner mouth as he is ejaculating following fellatio, irrumatio, or intercourse. The first explicit pegging scene is believed to have been in the 1975 pornographic film The Opening of Misty Beethoven. It is geared towards heterosexual men, who most typically define a threesome as such. Rainbow parties were covered on The Oprah Winfrey Show in 2003, and became the subject of a juvenile novel called hentai videos Rainbow Party. Group gay movies 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. Many fantasies include the macrophile shrinking before a normal sized woman or keeping his or her normal height while the partner grows in size. Common positions include lying on back or face down, sitting, squatting, kneeling or standing. A pornographic work is characterized as hardcore if it has any hardcore content, no matter how small. Its gain in prominence has been attributed to its depiction in the film Pecker, which was released in 1998.