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. The other person may do the same during or after. Urolagnia is a form of salirophilia in which sexual excitement is associated with the sight or thought of urine or urination. Macrophilia is a fascination with or a sexual fantasy involving giants, more commonly expressed as giantesses . Though there have lesbian milfs been numerous gang bang pornographic films since the 1980s, they usually involved no more than half a dozen to a dozen men. Perhaps following the example set by gay pornography, they have become a popular subgenre within heterosexual pornography since the turn of the century, featuring both vaginal and gaysex anal ejaculations. When the interest in a particular subject is obsessive, the behavior may be described as stalking. Sexual orientation Pornography features an increasing variety of combinations of actors by their sexual orientation such as lesbian, gay, bisexual, and transsexuals in addition to traditional heterosexual roles. Those with diaper-related paraphilias differ widely in their focus of attention. Women who perform in lesbian pornography often do not consider themselves lesbian or bisexual. Typically featured are hitting, choking, name-calling and hair-pulling. Rape pornography features performers simulating rape. Interactive pornography, available in CD-ROM and DVD format, allows the viewer to select the particular acts performed at any one time, sometimes with the camera providing a first person view. A woman can use a 3d hentai secondary vibrator, between the dildo and her genitals, to get pleasure from pegging. There are number of types of sex parties: Swinger party/gathering A swinger party or partner-swapping party is a gathering at which individuals or couples in a committed relationship can engage in sexual activities with others as a recreational or social activity. Spanking can be administered in a number of spanking positions.