Sexual excitement

As attraction develops further it leads to sexual excitement, during which all our senses as well as our intellect and emotions contribute to a need for sexual gratification. Feelings of excitement and tension are concentrated in our genital organs but also involve the whole body and mind. Things that lead to sexual excitement are called erotic stimuli.

Each of us has a complex individual pattern of stimuli that excite us sexually. The pattern grows and changes throughout our lives. Most people are stimulated by touching the genitals and other erotic zones (for example lips, tongue, breasts, buttocks, inner thighs). Our responses to sights, smells, tastes, sounds, fantasies and our surroundings are much more variable. It’s often said that the brain is the most important organ of sexual arousal, because if your thoughts and emotions aren’t attuned to sex (for example, if you’re angry with your partner), other erotic stimulation won’t turn you on.

As sexual excitement progresses, what happens to our bodies is mostly involuntary, though to some extent we can enhance or check it with our conscious minds. The body changes, known as the sexual response cycle, are described in four phases: arousal, plateau, orgasm and resolution.

Sexual response in women

During arousal,
the first response is an increased flow of blood to the pelvic and external genital organs. This has many important effects.

• The vagina is lubricated. Watery fluid seeps into the vagina, moistening its walls and flowing out to moisten the external genitals. No glands take part in vaginal lubrication (not even Bartholin’s glands, though their secretion can add to – but isn’t necessary for -lubrication around the vaginal opening later in the response cycle). The fluid comes from engorged blood vessels beneath the vaginal lining.

• The labia majora swell and open out.

• Labia minora become thicker, longer and bright red from engorgement with blood.

• The vaginal opening dilates.

• The clitoris enlarges and becomes harder.

As arousal progresses, more changes occur.

• Nipples become erect, and the areola around them swells and darkens. The breasts start to swell.

• The inner two-thirds of the vagina expands to become longer and wider. Its innermost third balloons out.

• The uterus and cervix become engorged and softer, and lift upwards in the pelvis.

• Blood pressure rises; pulse and breathing rates increase.

• Muscle tension increases throughout the body.

• A fine skin rash or ‘sex flush’ begins to develop on the chest, back and abdomen.

During the plateau
phase the changes of arousal develop further. Pelvic and genital engorgement increase; the inner vagina elongates and balloons further to reach up to three times its non-arousal diameter; the uterus swells and lifts higher; blood pressure, pulse rate, breathing rate and muscle tension increase; skin flush deepens.

There are three additional developments during the plateau phase.

• The lower third of the vagina decreases in diameter as it becomes markedly congested with blood. This constriction grips the penis during penetration, resulting in backward pulling on the labia and clitoral hood during penile thrusting.

• The clitoris shortens and disappears under its hood.

• The labia minora change colour from bright red to deep wine. This is a sign that orgasm is imminent.

What happens in orgasm?
The mounting tension of the plateau eventually triggers an initial spasm followed by a series of rhythmic contractions of the muscle surrounding the lower third of the vagina – the pubococcygeus muscle of the pelvic floor. At the same time rhythmic waves of contraction pass from the upper end of the uterus down to the cervix. The first few contractions occur at intervals of about four-fifths of a second. After that the intervals become longer and the intensity of the contractions tapers off. Muscle activity is the main source of the overwhelming, wonderful feelings of orgasm. The physical responses and sensations of orgasm can vary in intensity depending on mood, degree of arousal and other circumstances.

The events in the genital organs during orgasm are accompanied by changes in the rest of the body. Pulse and breathing rates, blood pressure and skin flush reach a peak. Spasm of various muscle groups leads to contortion of the face, arching of the spine, tightening of the abdomen and buttocks, clenching of the hands and feet, straightening of the ankles. Most of us are unaware of the extreme muscular exertions of orgasm.

After the muscular activity of orgasm has ceased, resolution begins. Orgasm initiates the release of muscle tension throughout the body and the release of blood from engorged blood vessels, with the following results.

• The swelling of the areola quickly subsides, making the erect nipple seem more prominent.

• The sex flush disappears and a film of perspiration appears on the skin.

• The clitoris promptly returns to its normal position, and over the next 5-10 minutes resumes its unaroused size.

• The muscles around the lower third of the vagina relax, and the vagina begins to return to its resting length and diameter.

• Swelling of the uterus subsides, and the uterus and cervix sink back into their usual position in the pelvis.

• The cervical canal dilates, perhaps to make it easier for sperm to pass through into the uterus.

• Blood pressure and pulse and breathing rates gradually return to normal.

When resolution is complete, most people feel blissfully relaxed and happy, and sleep quickly follows.

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