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Sexual Response Cycle
Sex therapists Masters and Johnson invented the Sexual Response Cycle, a term that refers to the sequence of events that happens to the body when a person becomes sexually aroused and participates in sexually stimulating activities, such as intercourse, masturbation, foreplay, etc..
The Sexual Response Cycle is divided into four phases: excitement, plateau, orgasm and resolution. They are all apart of a continuous process of Sexual Response; there’s no beginning or end to each phase.
Phase One: Excitement
Beginning within 10 to 30 seconds after erotic stimulation, this phase can last anywhere from a few minutes to many hours.
The man’s penis becomes slightly erect and his nipples may also become erect.
The woman’s vaginal lubrication begins, and the vagina expands and lengthens. The outer lips, inner lips, clitoris and sometimes breasts begin to swell.
In both partners, the heart rate, blood pressure and breathing are all accelerated.