Cultural history of the buttocks desirability of buttocks: Since the early 2000s, songs about the female buttocks have proliferated, especially in the hip-hop, reggae/dancehall, and R&B genres. Buttocks are often emphasized in pornography. Patricia Hill Collins, an African-American post-modern feminist writer, theorizes that this is derived from a stereotype that black women are promiscuous, and their buttocks are objectified by pornography as a result. A buttocks fetish or buttocks partialism refers to a condition wherein the buttocks becomes a primary focus of sexual attention. It may be associated with coprophilia, panty fetishism, eproctophilia, and sadomasochistic corporal punishment involving the buttocks. "Pygophilia" refers to sexual arousal
Sexual arousal changes in temperature associated with genital engorgement; this method directly measures changes in temperature of the labia. More recently, laser doppler imaging (LDI) has been used as a direct measure of genital sexual arousal in women. LDI functions by measuring superficial changes in blood flow in the vulvar tissues. Category-specificity refers to a person showing sexual arousal to the categories of people they prefer to have sex with. Sexual arousal studies involving category-specificity look at genital responses (physiological changes), as well as subjective responses (what people report their arousal levels to be). Category-specific sexual arousal is more commonly found amongst