The stages of sexual relation was first published by W.H Masters and V.E Johnson after a research that lasted more than 10 years and the results of this research were first published in the book called Human Sexual Response in 1966.
At the present day, the results of this research make up our fundamental knowledge about human sexual physiology.
Masters and Johnson observed human sexuality for the first time in a laboratory environment and in the studies that they conducted on hundreds of men and women volunteers, by observing directly the responses their test subjects gave to sexual stimuli and using objective measurement methods, they recorded every stage of the sexual response process.
Although there were certain changes in the later years, the model that Masters and Johnson’s established regarding the sexual response process, makes up the foundation of the contemporary categorizations of sexual dysfunctions.
Masters and Johnson have divided the physiological response given to sexual stimuli in humans into four different stages. In women and men, these stages are the same.
1) Excitement phase
2) Plateau phase
4) Resolution phase
It is the first phase in sexual functioning. Fundamentally, with the appearance of the erotic feelings and thoughts it causes erection in men and lubrication in women.
The body turns red and the muscles generally contract. In this period:
♦ In 10 to 40 seconds vagina starts to get wet
♦ Nipples rise and become visible, tits enlarge
♦ Uterus gets to be pulled up, big lips swell, clitoris bloats
♦ Small lips enlarge and swell
♦ The bottom part of the vagina widens
With the continuation of the effective sexual stimuli and rise of sexual excitement, man or woman, enters into the Plateau phase which is the second phase. In this phase, the feeling of pleasure and sexual tension rise and this state lasts up until the person’s orgasm phase.
♦ Sexual desires continue to rise
♦ There may be hot flashes and sweat in women
♦ Heart beats increase
♦ One third outer part of the vagina swells and widens through blood congestion
♦ On the upper part of the vagina there appears a puff, there may be slight pain
♦ Internal lips grows 2 to 3 times in size and their distances widen
♦ Vaginal entrance opens 8- In the small lips there appear slightly brown areas.
♦ The tip of the nipples (areolas) becomes visible and erect.
♦ The length of the tits grow approximately 25% (However, with women who have Brest fed before, this may not happen)
♦ Contractions occur in the legs
♦ The body of the woman is now ready for sexual intercourse
This is the phase which is shortest in duration but most intense in pleasure. This phase is characterized for men by ejaculation and for women by the reflexive rhythmic contractions occurring as a result of the enlargement of the tissues by the increase in blood that go to the muscles around the perineum and the vagina.
Rhythmic, ordered and simultaneous contractions are seen at 0.8-1 second intervals at the uterus, vagina and anus. Approximately 3 to 15 contractions occur. At this situation, certain changes are observed also in the brain waves of the women.
Moreover in this phase:
♦ There are temperature rise and sweating in the body
♦ Urethra hole may open and there may be urine flow to the outside (this situation is named as the “female ejaculation”)
♦ All the contractions in the body also reflect upon the woman’s face and it may seem like “the woman is feeling pain”
♦ At the peak point of orgasm, woman’s body almost becomes rigid like a “stone”.
If the sexual stimuli persist in the same intensity, several orgasms can occur. In reality, women are much luckier than men in this respect. Because, as men need time for rest about 15 to 30 minutes after orgasm, yet women may experience orgasms one after another in a single sexual intercourse period (multiple orgasm specialty). Even the number of experienced orgasms can reach up to 15 to 20 (for the ones who are lucky).
It is characterized by the process, in men and women after orgasm or in cases where orgasm is not achieved, the physiological changes that have occurred in the genitalia and in other parts of the body after the Plateau phase recede one by one in their order of occurrence in minutes
The duration of the resolution phase varies by sex, whether an orgasm is experienced or not or experienced in what intensity and whether sexual stimuli still persist or not.
In this phase:
♦ Fast breathing and sweating are observed
♦ The vagina, the tits, the inner and outer lips and the clitoris recede back to their initial state
♦ The clitoris and the nipples become sensual and receptive to pain
♦ Fever decreases
♦ Heart beats first increase then go back to normal
These four phases are still valid under the light of our current knowledge. However, the stages that are crucially important in categorizing sexual dysfunctions and in regard to disjunctive diagnosis and treatments are “excitement” and “orgasm” phases.
The “Plateau” phase is actually considered physiologically as a part of the “excitement” phase. As the numbers of sexual problems or sexual dysfunctions intrinsic to the “resolution” phase are at a quite negligible level, psychological categorizations do not base upon the “resolution” phase.
According to Masters and Johnson, sexual dysfunction is one of the several impediments in human sexual response cycle that can cause insufficiency in reaching satisfactory sexual stimulation or satisfaction. Again, according to the researchers, among 50% of the married couples, there are sexual dysfunctions.
Helen Singer Kaplan, who is one of the founders of sex therapy, in her book The New Sex Therapy published in 1974 and not much renown previously, has portrayed the diphasic nature of sexual response in humans.
According to Kaplan, the sexual response, in reality rather than being a single and independent whole, comprises of two relatively independent stages.
These sections are:
⇒ Tthe increase of the genital blood flow that provides erection in men (penial erection) and vaginal wetting (lubrication) in women and enlarging-swelling.
⇒ Reflex, rhythmic muscle contractions that provide orgasm in both sexes.
The increase of the genital blood flow that falls into the Excitement and Plateau phases of the Masters and Johnson stages are stimulated by the “parasympathetic nervous system” yet the second stage defined by muscle contractions and falls into the Orgasm phase, is stimulated by the “sympathetic nervous system”.
Kaplan has determined that 50% of men encounter temporary erection adversity and has stated that this is normal.
Again, according Kaplan, the most frequently seen male sexual dysfunction is premature ejaculation.