Sex researchers William Masters and Virginia Johnson were the first to propose a 'four phase' model of sexual response. They based their ideas on experimental research with adults where they both observed adults engaging in sexual behaviors and measured what happens to the body during sexual activity.
Here is how they break down male sexual response:
Phase 1 - ExcitementIn response to sexual stimuli (whether psychological in the form of sexual thoughts or fantasies, or physical in the form of physical stimulation) the process of vasocongestion occurs, where more blood flows into the penis than is flowing out, and the result will usually be that a man will get an erection. How long this takes, and what the erection feels like will differ from man to man, and for the same man over time. Physical changes may include:
- There are also changes in the scrotum and testes, with the testes increasing in size and the scrotum elevating, coming closer to the body.
- The skin may become flushed, men may experience heightened sensitivity in parts of their body, like the nipples.
- Some increase in heart rate, blood pressure, and muscle tension.
Phase 2 - PlateauWith continued sexual stimulation this phase represents the time between the initial arousal and excitement, up until orgasm. For many men the plateau phase is very short, but this is the phase that men can extend as a way of controlling premature ejaculation. Physical changes during this phase may include:
- An increase in the size of the head of the penis, and the head may also change color, becoming purplish.
- The Cowper's gland secretes fluid, often referred to as pre-cum , which comes out of the tip of the penis.
- The testes move further in towards the body, and increase in size.
- There may be a sex flush, muscle tension, increase in heart rate and rising blood pressure.
Phase 3 - OrgasmMasters and Johnson further divided the orgasmic phase for men into two separate stages. In the first stage:
- Contractions in the vas deferens, seminal vesicles, and the prostate causes seminal fluid (semen or ejaculate) to collect in a pool at the base of the penis, in the urethra.
- This collection is usually felt as a tickling type sensation.
- Contractions of muscles occur in a throbbing manner around the urethra, and propel ejaculate through the urethra and out of the body.
- These contractions (which occur at different speeds, and in different amounts) are usually what are experienced as highly pleasurable feelings of release.
Phase 4 - ResolutionResolution phase refers to the period of time immediately following an orgasm, when the body begins to return to its 'normal' state. This phase includes:
- The loss of the erection as the blood flows out of the penis, which happens in two stages over the period of a few minutes.
- The scrotum and testes return to normal size.
- A general feeling of relaxation.
- There is also a refractory period following ejaculation when a man is physically incapable of getting another erection. This period may be from a few minutes to much longer. It seems to be longer in older men, although there are many possible individual differences.
While this description of male sexual response can be a helpful way to start thinking about your own sexual response, try not to use it as a strict guide to measure yourself against. For one thing, the description only deals with physical changes in your body. Your sexual response is much more than blood flow and lubrication.
If youre experience is different it doesn't necessarily mean there is anything wrong with you. While there are some generalities, the reality is that everyone is different, and everyones sexual response may be a bit different too. There are limitations to the research that Masters and Johnson conducted, and some researchers argue that separating sexual response into stages doesn't make any sense at all.
Masters, W.H. & Johnson, V.E. Human Sexual Response New York: Bantam Books, 1980.