Human sexual response is defined, at the most basic level, as a biochemical and physiological response to sexual stimulation that occurs in men and women after puberty. The sexual response cycle refers to the sequence of physical and emotional changes that occur as a person becomes sexually aroused and participates in sexually stimulating activities, including intercourse and masturbation. Understanding physiological responses during a sexual experience can help people know how their bodies should typically respond and can help professionals identify possible physical, psychological, or relational problems that might be influencing sexual responses. In order to aid in understanding, researching, and intervening with sexual functioning, several models of human sexual response have been developed, including a four-phase model by Virginia Masters and William Johnson, a three-phase ...