There are two major components of physiological response. The first is vasocongestion, an increased flow of blood in various parts of the body. In women, vasocongestion occurs most notably in the clitoris and external genitalia, which become engorged during sexual arousal (though not rigid). Increased blood flow also leads to increased vaginal lubrication. The second component of physiological response is a process in which neurotransmitters produce heightened levels of neuromuscular tension – more energy in the nerves and muscles. As a result of these two responses, we may experience heightened sensitivity anywhere from the fingertips to the lips to the genital organs.
The most widely used framework for understanding the workings of the body during a sexual encounter, known as the sexual response cycle, comes from the famous sex researchers William H. Masters, MD, a gynecologist, and Virginia E. Johnson, a psychologist. They describe the process by dividing it into four stages: excitement, plateau, orgasm, and resolution.
The process of sexual arousal is a body mind response triggered by any signal we interpret as erotic. These signals may be sensual – a touch, a smell, a visual cue – or they may have to do entirely with internal stimuli, such as a fantasy, memory, or sexual thought. Whatever the trigger, the process of arousal depends on chemical messengers known as neurotransmitters. These elements of the nervous system set into motion the physical changes we experience as sexual arousal.
Vasocongestion and neuromuscular tension bring about changes such as sex flush (which is more common in women than in men) and erect nipples. Heart rate quickens, muscles respond, and blood begins to rush to other parts of the body, including the breasts, the vulva, and the vagina.
The vulva refers to the external genitals, including the clitoris, urethra, labia majora (outer lips), labia minora (inner lips), and the vaginal introitus (the vaginal opening). The vagina, strictly speaking, is an internal cylindrical organ about three to four inches long surrounded by muscle and lined with mucous membranes. The vagina ends at the cervix, the opening to the uterus, which is the expandable internal organ where the fetus grows and develops before birth.
One of the first changes is lubrication (wetness in the vagina). It is the direct result of vasocongestion in the walls of the vagina, causing fluid that is stored in the vaginal lining to seep through. Lubrication is also provided by the Bartholin’s glands, small glands located in the vulva near the opening of the vagina. Lubrication is a gradual process and may not be noticeable until the fluid begins to gather and trickle towards the vaginal opening. Meanwhile, the expandable interior of the vagina becomes deeper and wider.
In the vulva, the labia minora thicken, and the labia majora open back to expose more of the vaginal opening. In addition, the clitoris becomes firmer and more sensitive, and it pulls back under its hood.
The clitoris is the center of sexual stimulation for most women. It’s a small, elongated, erectile body at the very top of the vulva with the sole function of providing sexual pleasure. The clitoral hood is connected to the vaginal lips. During vaginal intercourse, the penis moves in and out of the vagina and tugs on the labia, causing indirect clitoral stimulation. The size of the clitoris and its distance from the vaginal opening vary from woman to woman. Depending on the size and position of the clitoris and its hood, direct stimulation may be needed to produce an orgasm. However, direct stimulation should be approached with caution since the clitoris can become hypersensitive when aroused.
A key sign of plateau in women is something called the orgasmic platform, a marked swelling of the walls in the outer third of the vagina (near the vaginal opening). As Masters and Johnson note, in vaginal intercourse, this nerve-rich platform can effectively grasp the shaft of a penis, whatever its size.
Lubrication continues during the plateau phase but may wax and wane as does an erection. The inner two-thirds of the vagina expand further in width and depth. And the clitoris enlarges but pulls back against the pubic bone. This, together with the swelling of the vaginal lips, makes clitoris harder to locate beneath its hood.
Because of the continued pooling of blood, vaginal lips may turn red, sex flush may intensify and spread, and the area around the nipples may become swollen.
Apparently not. Although there are many parallels between male and female sexual response, women do not seem to have an equivalent mechanism of orgasmic inevitability. A woman can be on the verge of orgasm and be deterred at the last second by any number of distractions or a failure of stimulation.
Most women report that their first sensations of orgasm are feelings of intense warmth and pleasure centering on the clitoris. For most women, it is stimulation of the clitoris that brings them to this moment. As in men, orgasm involves a series of involuntary contractions, which in women involve the orgasmic platform, the uterus, and anus.
Surprisingly, the rate of orgasmic contraction is the same in men as in women – less than 1 second apart – and sensations at the moment of climax don’t differ much either. Written descriptions of orgasm by men and women are virtually identical when no reference is made to anatomy or ejaculation.
One big difference is ejaculation. As we mentioned earlier, men usually ejaculate when they climax. Some women report having an ejaculation, which may be a buildup of vaginal secretions that lubricate the vagina during sex or may be the release of urine. The existence of an independently functioning process of female ejaculation remains scientifically unproved, although a number of women attest to it.
Multiple orgasm is defined as two or more orgasms per single act of sex. Although fewer than half of orgasmic women have ever had multiple orgasm, many sexologists believe all women have the potential. Men, by contrast, are substantially less capable of multiple orgasm, though it’s not impossible.
Clarifying expectations may be the first step. In that spirit, some therapists prefer using the term ‘serial orgasm’ rather than ‘multiple orgasm’ because for many women successive orgasms will not follow immediately, hard atop one another, with no downtime in between. The pattern of serial orgasm varies from woman to woman.
The first step is to continue stimulation after the first orgasm, something not every partner thinks to provide. However, some women don’t respond positively to clitoral stimulation immediately after orgasm because the clitoris is hypersensitive. One solution may be to wait a few seconds after orgasm, keep breathing rhythmically, and then continue with gentler stimulation.
A word of caution: Some experts point out that focusing too much on multiple orgasm tends to be counterproductive and can interfere with sexual pleasure. A woman’s level of sexual satisfaction is not necessarily linked to the number of orgasms she experiences per sex act.
This goes back to the Masters and Johnson model and the final stage of sexual arousal – resolution. This phase immediately follows orgasm and consists of the time it takes for the body to return to an unaroused state.
Though both sexes experience resolution after climax, there are certain differences between male and female response. For most men, the resolution phase is also a refractory period, lasting at least a few minutes, during which they are unable to have another climax even if the penis is still erect and stimulation continues. Women do not have a refractory period, which means they have the potential to reenter the plateau stage right after one orgasm and have another (or several) before reaching resolution.
Some experts say that a small percentage of men have no refractory period and thus can be multiorgasmic. Some men can learn to have multiple orgasms, researchers say, by developing the ability to separate orgasm from ejaculation and thereby have one or more climaxes before ejaculating.
A small percentage of men – roughly 10% – have difficulty reaching orgasm, and anywhere from 25% to 50% of women do not climax consistently with intercourse.
