While anal sex is commonly associated with male homosexuality, research shows that not all gay males engage in anal sex and that it is not uncommon in heterosexual relationships. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Foot fetish pornography features heavy emphasis on the feet of the participants, gaysex either in combination with kissing and genital sex or in the context of acts such as trampling or crush fetishism. Voyeur pornography may also include shots of topless women on topless beaches who are unaware of the cameras but may legally be photographed due to the public setting. Examples of mentally oriented practices are education games, during which the dominant requires certain forms of behavior from the submissive. In humans, females generally have more round and voluptuous buttocks, caused by estrogen that encourages the body to store fat in the buttocks, hips, and thighs. The naked appearance of actress Demi Moore in the advanced stage of pregnancy on the cover of Vanity Fair magazine in 1991 marked the beginning of a period which has since seen pregnancy presented by celebrities as a glamorous state of living, while also creating a market for photographers to produce images of pregnant mothers, and for fashion stylists to introduce pregnancy styling to their business. Sigmund Freud considered foot anime hentai binding as a form of fetishism. 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 . Common positions include lesbian milfs lying on back or face down, sitting, squatting, kneeling or standing. Felching is a sexual practice involving the act of orally sucking semen out of the vagina or anus of one partner. The reverse of this, in which nude women interact with clothed men, is called Clothed male, naked female .
