has just launched its fully updated site as of May 27, 2024. Please contact us at for any questions or need for user support.



As a starting point for this course, we will begin with an exploration of several components of normal sexuality. Our first key area of foundational knowledge concerns the sexual response cycle. Sexual response refers to the basic physiologic changes that occur with any type of sexual stimulation including masturbation, manual stimulation by one's partner, oral sex, penile-vaginal intercourse, anal sex, fantasy, etc.

While there are many individual differences in physical, mental, and emotional reactions, there are general predictable patterns that happen with sexual arousal. These tend to be similar across cultures.

Different researchers have developed various models of sexual response. Usually these models include three, four, or five distinct phases, with the exact components of each phase differing across models. The two most well known models are included in this course: the Masters and Johnson Model and the Kaplan Model.

Descriptions of these models are not meant to lead to viewing the sexual response as a mechanized, impersonal response or set of expectations that one must “master.” Viewing them as such can lead to “spectatoring,” i.e., remaining outside oneself as an observer and gauging one’s responses and performance.

Sexuality Factoid

19% of women think about sex everyday or several times a day, 67% a few times per month or a few times per week, and 14% less than once a month

Source: Laumann, E., Gagnon, J.H., Michael, R.T., and Michaels, S. The Social Organization of Sexuality: Sexual Practices in the United States. 1994. Chicago: University of Chicago Press


The following information, written by the Sinclair Intimacy Institute (2002), is taken largely from the website
and represents an excellent synthesis of the Masters and Johnson (1966) model of sexual response.

William Masters and Virginia Johnson, prominent sex researchers and therapists, proposed four phases in the sex response cycle: excitement, plateau, orgasm, and resolution. Using various instruments designed to monitor changes in heart rate and muscle tension, Masters and Johnson were able specify the bodily changes that characterize each of these phases.

1) The First Phase—Excitement

Excitement can last for just a few minutes or can be extended for several hours. Characteristics of this phase include: an increasing level of muscle tension, increased heart rate, hardened or erect nipples, and the onset of vasocongestion, resulting in swelling of the woman's clitoris and labia minora, elevation and engorgement of the man’s testes, and erection of the penis. In addition, sex flush occurs in some women and men, i.e. flushed skin (or some blotches of redness on the chest and back).

Other changes that occur in the woman are: the vaginal walls begin to produce a lubricating liquid early in the excitement phase, her uterus elevates and grows in size, and her breasts become larger. At the same time, her vagina swells and the muscle that surrounds the vaginal opening, called the pubococcygeal muscle, grows tighter.

These changes prepare her body for orgasm and were called the "orgasmic platform" by Masters and Johnson. Additional changes in men include elevation and swelling of the testicles, tightening of the scrotal sac, and secretion of a clear lubricating fluid (known as pre-ejaculate) by the Cowper's glands.

2) The Second Phase—Plateau

The plateau phase, generally lasting from a few seconds to a few minutes, is characterized primarily by the intensification of all of the changes begun during the excitement phase—there is no clear starting point that marks a shift from the excitement phase. Some people find that extending the length of the plateau period can lead to more intense orgasms. In this period, the woman's clitoris may become so sensitive that it is painful to the touch. The plateau phase extends to the brink of orgasm.

3) The Third Phase—Orgasm

The peak of sexual response is reached during the third phase, i.e., orgasm, generally the shortest phase of the sexual response cycle, lasting only several seconds. Involuntary muscle contractions, heightened blood pressure and heart rate, rapid intake of oxygen, sphincter muscle contraction, spasms of the carpopedel muscles in the feet, and sudden forceful release of sexual tension characterize the orgasmic phase in men and women. For women, contractions of the uterus can also occur with orgasm.

Women can have a slightly longer orgasm than men. Some women (actual numbers are not known, and estimates vary widely, but probably at least 10-15%) experience the plateau phase without reaching orgasm. It is known that there are much greater numbers of women than men who do not experience orgasm. Interventions for anorgasmia (a.k.a., inorgasmia) will be discussed in the Female Sexuality section of the course.

At the onset of ejaculation in men, the intact internal sphincter of the urinary bladder normally closes or remains closed, thereby preventing seminal fluid from going backward into the bladder (retrograde ejaculation) and also preventing any intermingling of urine and seminal fluid.

Usually men experience orgasm and ejaculation of semen in conjunction with each other, but ejaculation does not always occur at the time of orgasm. Ejaculation consists of two steps. During the first phase, called the emission phase, seminal fluid builds up in the urethral bulb of the prostate gland. As the fluid accumulates, the male senses he is about to ejaculate. This is often experienced as inevitable and uncontrollable and is referred to as the point of ejaculatory inevitability.

Unless there is some type of sexual dysfunction, orgasm is an intensely pleasurable experience for males and females. Frequently people have questioned the differences in the subjective experiences of male and female orgasm and whether one is more pleasurable than the other. Study data suggests that orgasms do not seem to differ by gender; that is, men and women feel quite similar things during orgasm.

In one study, college students provided descriptions of orgasm. Researchers compared these descriptions using a standard psychological rating scale, and there were no distinguishable differences between men's and women's descriptions. Both males and females tended to describe orgasm with words such as "waves of pleasure in my body," corresponding to the rhythmic muscle contractions that occur during orgasm.

In an earlier study, 70 expert judges could not reliably differentiate between the reports of orgasms in men and women. One personal report from a male to female transsexual who has experienced orgasms as both genders stated that she could tell little to no difference in the orgasms she felt as a male and those she currently enjoys as a female.

4) The Final Phase—Resolution

In the resolution phase, which begins immediately after orgasm, the body returns to its original, non-excited state if there is no additional stimulation. Some of the changes occur rapidly, whereas others take more time.

The resolution phase is marked by a general sense of well-being and enhanced intimacy and possibly by fatigue as well. Many women are capable of a rapid return to the orgasmic phase with minimal stimulation and may experience continued orgasms for up to an hour and sometimes longer.

Refractory Period

Males, especially as they age, experience a refractory period of varying duration after orgasm. During this period, men cannot be re-stimulated to excitement, plateau, or orgasm. The duration of the refractory period can vary from just a few minutes to several days, depending on age and frequency of sexual activity, among other things, and there is great variability in the length of the refractory period both within and between men.

Women typically do not experience a refractory period, and they are capable of reaching orgasm from any point during resolution. Although women have the potential to have multiple orgasms, a woman may not want to have more than one during a lovemaking period. Once again, communication between partners is important in determining individual preferences.


Helen Singer Kaplan (1983) described three stages of sexual response: desire, excitement, and orgasm. The Sexual Health Network (2004) states, “The inclusion of desire as part of the human sexual response cycle leads to consideration of psychological and physical factors that may impact sexual desire. Factors that might block sexual desire include stress, fatigue, depression, pain, fear, some prescribed medication and recreational drugs, negative past sexual experiences, power and control issues in a relationship, loss of interest in a partner, low self-image, and hormonal influences. Many of these factors are associated with early stages of disability or illness” (Sexual Health Network, 2004).

In terms of the experience of desire, some people who have no desire prior to beginning a sexual encounter will develop desire once the experience has begun. This has been likened by some to the difference in a gas stove and an electric stove, i.e. for some people the flame and heat are available immediately, while others require a period of heating up in order to become involved.

This experience is described in a third model of sexual response developed in recent years by Rosemary Basson and her colleagues. The Basson Model suggests that women’s sexual response is not necessarily linear, but that desire and arousal can develop after a decision is made to engage in a sexual encounter and/or after sexual activity has begun (Basson, 2005).

Also, some couples may engage in sexual activity when no desire is present for either of them, such as with couples who are trying to conceive a child. Desire and sexual expression can take many forms. One partner who has little to no desire at a given time may participate in a sexual experience for a variety of reasons, including love for the partner. This will be discussed in an upcoming section of the course.

A final note on sexual responses: while sexual responses are biologically somewhat predictable, there is wide variability in each person’s subjective experience. In addressing this, noted sex educator Pat Koch states:

“Whenever I talk about sexual responding with groups (of different ages, contexts, etc.), I try to stay away from having them think about a ‘model’ of sexual response since I think that sets them up for ‘performance pressure.’ Here is the approach that I like to use from a book I wrote—Exploring Our Sexuality: An Interactive Text: “‘As each of us is unique, so are our sexual responses. Sexual responding is a complex physical, psychological, social, for many, spiritual process. There is no single correct pattern of sexual response which all people should follow. On the contrary, there are many varieties of sexual response among women and men and even within the same individual. A person may respond differently to self-stimulation than with different partners. A person is even quite likely to respond differently at different times with the same partner because of the context of the situation (a romantic evening in an exotic setting versus the back seat of a car), the state of the relationship (the first time versus after many years together), or the events happening in his or her life (spring break versus finals time). Such variation in sexual response is all completely natural.” (Koch, 1995, p. 265).


Generally the American idea of sex is a stair step progression to the top step, with intercourse and orgasm as the goal. Indeed, the top step is envisioned to end with the R.T., the Real Thing, which the literature tells us is “multiorgasmic simultaneous orgasm in intercourse for both people.” This is almost always a fantasy, but people aspire to get as close as possible, frequently devaluing and even overlooking pleasurable and enjoyable sexual expression. Often when people are not having intercourse, for whatever reason, they stop touching, sometimes virtually altogether.

Perhaps a better way to view sexual expression is as a circle with many life affirming and relationship enhancing activities possible—the concept of non-goal-directed sex. Health care practitioners can be a very important source of information and support in this area, by challenging the widely held notion that other behaviors “don’t count,” by exploring options for touching and intimate connection, and by supporting expressions of sexuality that are enjoyable and life-affirming. (Original source unknown).

The American Idea of Sex      VS.        Non Goal-Directed Sex

One approach that has begun to take shape as a counterpoint to the American Idea of Sex can be found in the New View Campaign. We will examine this in our next section.