and mutual masturbation" among both sexual orientations in prevalence. Wellings et al. reported that "the equation of 'homosexual' with 'anal' sex among men is common among lay and health professionals alike" and that "yet an Internet survey of 180,000 MSM across Europe (EMIS, 2011) showed that oral sex was most commonly practised, followed by mutual masturbation, with anal intercourse in third place". Female to male Women may sexually stimulate a man's anus by fingering the exterior or interior areas of the anus; they may also stimulate the perineum (which, for males, is between the base of the scrotum and the anus), massage the prostate or engage in anilingus. Sex toys, such as a dildo, may also be used. The practice of a woman penetrating a man's anus with a strap-on dildo for sexual activity is called pegging. It is common for heterosexual men to reject being receptive partners during anal sex because they believe it is a feminine act, can make them vulnerable, or contradicts their sexual orientation; they may believe being a receptive partner is indicative that they are gay. Reece et al. reported in 2010 that receptive anal intercourse is infrequent among men overall, stating that "an estimated 7% of men 14 to 94 years old reported being a receptive partner during anal intercourse". The BMJ stated in 1999: Female to female With regard to lesbian sexual practices, anal sex includes fingering, use of a dildo or other sex toys, or anilingus. There is less research on anal sexual activity among women who have sex with women compared to couples of other sexual orientations. In 1987, a non-scientific study (Munson) was conducted of more than 100 members of a lesbian social organization in Colorado. When asked what techniques they used in their last ten sexual encounters, lesbians in their 30s were twice as likely as other age groups to engage in anal stimulation (with a finger or dildo). A 2014 study of partnered lesbian women in Canada and the U.S. found that 7% engaged in anal stimulation or penetration at least once a week; about 10% did so monthly and 70% did not at all. Anilingus is also less often practiced among female same-sex couples. Health risks General risks Anal sex can expose its participants to two principal dangers: infections due to the high number of infectious microorganisms not found elsewhere on the body, and physical damage to