Snuff pornography involves the actual death of any of the participants, consenting or otherwise, simulated death is not considered snuff. BDSM is a variety of erotic practices involving dominance and submission, role-playing, restraint, and other interpersonal dynamics. Incest pornography can feature actual relatives, but the main type of this pornography simply uses actors of similar looks to suggest family relationship. See Gay-for-pay. If this is done using penises and/or strap-on dildos, this is sometimes called the sandwich or BigMac. Mutual masturbation is a sexual act where two or more people stimulate themselves or one another sexually, usually with the hands. Mammary intercourse is said by Alex Comfort to produce mutual orgasm in women with sensitive breasts , and it was one of the nine substitute exercises for penetrative sexual activities, as detailed in the Paradis Charnels of 1903. In addition to mainstream pornography, the popularity of facials has led to creation of its own niche market, like video series that specialize in showing the act. The work of Bruce Seven has been called reality porn, due to his lack of using scripts and asking his performers to act naturally in their own character. This style of filming is in contrast to having a separate, third-person videos gays camera crew filming all the action. Animal masturbation has been observed in many species, both in the wild and in captivity. Watersports pornography features sexual activities involving urine, such as golden showers. Interracial pornography typically employs ethnic and racial stereotypes in its depiction of performers and many of interracial pornographic films still include racial stereotypes, although the 3d hentai segregation of actors by race has diminished considerably. Bobbi porn milf S. A variation on this is to place the fingers and thumb on the penis as if playing a flute, and then shuttle them back and forth. Homi Bhabha defined the idea of a racial fetish in contrast to the idea of the Freudian sexual fetish which he describes a denial of difference, where the male sees the female as a castrated male, seeing missing parts rather than a different anatomy.