Masters and Johnson argued that, in the first stage, "accessory organs contract and the male can feel the ejaculation coming; two to three seconds later the ejaculation occurs, which the man cannot constrain, delay, or in any way control" and that, in the second stage, "the male feels pleasurable contractions during ejaculation, reporting greater pleasure tied to a greater volume of ejaculate".They reported that, unlike females, "for the man the resolution phase includes a superimposed refractory period" and added that "many males below the age of 30, but relatively few thereafter, have the ability to ejaculate frequently and are subject to only very short refractory periods during the resolution phase".
These effects impact cultural views of orgasm, such as the beliefs that orgasm and the frequency/consistency of it are important or irrelevant for satisfaction in a sexual relationship, In a clinical context, orgasm is usually defined strictly by the muscular contractions involved during sexual activity, along with the characteristic patterns of change in heart rate, blood pressure, and often respiration rate and depth.
There is some debate whether certain types of sexual sensations should be accurately classified as orgasms, including female orgasms caused by G-spot stimulation alone, and the demonstration of extended or continuous orgasms lasting several minutes or even an hour.
Sexual stimulation can be by self-practice (masturbation) or with a sex partner (penetrative sex, non-penetrative sex, or other sexual activity).
The health effects surrounding the human orgasm are diverse.
It can additionally be achieved by stimulation of the nipples or other erogenous zones, though this is rarer.
or an involuntary orgasm, such as in the case of rape or other sexual assault.
There are many physiological responses during sexual activity, including a relaxed state created by prolactin, as well as changes in the central nervous system such as a temporary decrease in the metabolic activity of large parts of the cerebral cortex while there is no change or increased metabolic activity in the limbic (i.e., "bordering") areas of the brain.
There is also a wide range of sexual dysfunctions, such as anorgasmia.
It is believed that the amount by which oxytocin is increased may affect the length of each refractory period.
A scientific study to successfully document natural, fully ejaculatory, multiple orgasms in an adult man was conducted at Rutgers University in 1995.
Masters and Johnson equated male orgasm and ejaculation and maintained the necessity for a refractory period between orgasms.