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Phase 2: Plateau
General characteristics of the plateau phase, which extends to the brink of orgasm, include the following:
- The changes begun in phase 1 are intensified.
- The vagina continues to swell from increased blood flow, and the vaginal walls turn a dark purple.
- The woman's clitoris becomes highly sensitive (may even be painful to touch) and retracts under the clitoral hood to avoid direct stimulation from the penis.
- The man's testicles are withdrawn up into the scrotum.
- Breathing, heart rate, and blood pressure continue to increase.
- Muscle spasms may begin in the feet, face, and hands.
- Muscle tension increases.
Phase 3: Orgasm
The orgasm is the climax of the sexual response cycle. It is the shortest of the phases and generally lasts only a few seconds. General characteristics of this phase include the following:
- Involuntary muscle contractions begin.
- Blood pressure, heart rate, and breathing are at their highest rates, with a rapid intake of oxygen.
- Muscles in the feet spasm.
- There is a sudden, forceful release of sexual tension.
- In women, the muscles of the vagina contract. The uterus also undergoes rhythmic contractions.
- In men, rhythmic contractions of the muscles at the base of the penis result in the ejaculation of semen.
- A rash, or "sex flush" may appear over the entire body.