Particular areas and processes of the body that change during pregnancy may also become the focus of psychological investment, but nudity or sexual activity is not always essential, and in some cases actual pregnancy is not necessary to invoke arousal. Oral sex pornography frequently features a person performing fellatio, and less frequently cunnilingus. Reality pornography is professionally made porn which seeks to emulate the style of amateur pornography. Female ejaculation is the expulsion of fluid by the paraurethral ducts through and around the human female urethra during or before an orgasm. In human sexuality, a threesome is sexual activity that involves three people at the same time. Mammary intercourse is a sex act, performed as foreplay or as non-penetrative sex, that involves the stimulation of the male penis by lesbian hentai the female breasts and vice versa. The wife who enjoys cuckolding her husband is frequently called a gay sex video hotwife, or a cuckoldress if the man is more submissive. The existence of such content in commercially available pornography is widely considered an urban legend. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. The term combines elements of the Freudian psychoanalytic fetish and the Marxist commodity fetish, and is used in the context of British, Spanish and French colonialism and imperialism and their aftereffects. The definition clash also appears with the English definition of yuri as any lesbian relationship, as opposed to its sexually explicit definition in Japan. The person receiving anilingus is regarded as the passive partner in the act, and the person performing anilingus is the active partner. Bisexual pornography is a genre of pornography which most typically depicts one woman and two men who all perform sex acts on each other. Women oriented pornography is sometimes referred to as sex positive pornography. Macrophilia is a momporn fascination with or a sexual fantasy involving giants, more commonly expressed as giantesses .