Male Sex Response
Written by Matt Butcher:
The course of sexual activity runs through 4 general stages in both men and women: excitement, plateau, orgasmic, and finally resolution, or returning to an unstimulated state. There are no sharply defined boundaries between these phases, so they are used only for reference and convenience. Below is a detailed guide to the various sexual changes found in men throughout all 4 of these stages:
Excitement (Oh yeah!)
The first sign of sexual arousal in men, of course, is the erection of the penis. This can be triggered through physical stimulation, through pleasant sights, or an erotic train of thought, or any combination of these. Once stimulation begins, the erection generally occurs within a few seconds. During this erection, a smaller penis may more than double in length. In larger penises, this lengthening is less dramatic. There is far less variation in the size of erect penises among men than for limp ones. This erection is caused because there is more blood entering the penis than leaving it, so it swells until it can hold no more blood and excess is finally forced out.
In addition to the obvious changes in the blood supply of the penis, the blood supply of many other organs also changes. This is the primary response to sexual stimuli. The second is the contraction of various muscle fibers and groups of muscles all over the body. Eventually the breasts of some men may undergo some changes, although much less dramatically than women. In 3/5 of the male population the nipples may become at least partially erect, usually one before the other. Also, about a quarter of the male population develops a sex flush sometime during the course of stimulation, a measles-like rash that starts on the stomach, chest, or back and spreads over the breast and eventually over the rest of the body.
Changes are also obvious in the testicles and scrotum during the excitement phase. The skin of the scrotum tenses up and thickens, and the whole sack is elevated towards the body. The epididymis (the spermatic cord that suspends the testicle) also shorten, pulling them yet closer towards the body. Just as one nipple may become erect before the other, one testicle may ascend before the other does.
Plateau (We're getting there!)
The erection of the penis is usually completed during excitement, and the only further changes in it may be an increase in the size and diameter of the coronal ridge of the penis head, and a deepening color of the organ. The testicles increase in size, with a 50% increase in diameter in most men, and they draw yet closer to the body with a further tightening of the sack and epididymis. If the man's nipples weren't erect earlier, they may be now. The rate of breathing increases during this phase, along with a rise in pulse and blood pressure. The sex flush may also appear now, if it didn't earlier, or if it has it may become more widespread and obvious. The tension of voluntary and involuntary muscles is heightened; almost spasmic contractions may be present in the face, ribs, and abdomen. The sphincter (asshole) may also tighten up, and some men even tighten it intentionally as a means for increasing the sexual tension.
A few drops of moisture may emerge from penis during this phase. It comes (no pun intended) from the Cowper's glands, the male equivalent of the female Bartholin's glands. The fluid, sometimes referred to as "precum" isn't semen, but it is important to know that this fluid can contain thousands of sperm. This means it is entirely possible for the woman to become pregnant, even if he withdraws or plans to withdraw his penis before ejaculation.
Although many of these changes may seem different in men and women, they are all closely related to increases in muscle tension and the engorgement of various organs, both sexual and non-sexual, in both sexes. The apparent peak of this tension is reached when the man reaches the third stage of stimulation, the orgasm.
The most prominent feature of the male orgasm is the contractions of various muscle groups, including the ejaculation of semen, and an overall euphoric feeling that is centralized in the lower abdomen. This feeling may last throughout most of the ejaculation process. These contractions are generally at around 4/5 of a second, and tend to taper off after the initial burst.
Ejaculation, although it occurs rather quickly, is a rather complex process. Before the orgasm is reached, fluid containing millions of sperm from the testicles collects in the seminal vesicles in a pair of small flask-like organs known as ampullae. These organs then contract rhythmically and expel the fluid into the urethra (the tube that runs from the hole in the tip of the penis back inside the body to the bladder). At the same time, the prostate contracts and sends prostatic fluid into the urethra. A bulb in the urethra near the base of the penis then doubles or triples in size to receive the fluids. Next, a series of rhythmic contractions of this bulb shoots the fluid out under high pressure, shooting perhaps 2 feet beyond the tip of the penis, or farther, if not contained. In older men these contractions are less vigorous, and this pressure will probably be much lower. The urethra itself may continue to undergo minor contractions, even after the contractions of the penis are no longer noticeable.
In addition to these obvious and well-known events, the body undergoes other changes during orgasm. Pulse rate, breathing rate, and blood pressure reach a peak. The sex flush is strongest now. Muscles all over the body respond in various ways. The face, for example, might be contorted into a grimace through the tightening of some muscles. Other muscle groups in the arms and legs may spasm, and often partners will grasp each other to embrace themselves. Most people aren't really aware of these changes, and as a result some people might experience minor muscle aches the next day.
One major function of the orgasm becomes apparent soon after it ends. It releases all the stored sexual and muscular tensions and initiates the release of blood from engorged organs. The penis returns to its flaccid state, and the testicles gradually descend back into their unstimulated state. Breathing rate, pulse, and blood pressure return to normal levels. A significant feature of the male resolution phase is the refractory period. During this period a man can't become aroused or have another erection. In some men, especially teenagers, this period may be quite brief, a few minutes, while in older men it may last for hours or longer. An hour is about the average refractory period duration. Women don't have this peculiar feature, if they are further stimulated shortly after orgasm, they may experience further excitement and may even have additional orgasms.
None of the details of sexual arousal above may accurately describe any one man, everyone is different in their own manner of response. This is just a general guide of what often or usually takes place, often men and women won't show all the features listed, and could even show signs not even mentioned. Another important thing to note is the fact that these phases occur almost exactly the same no matter what the source of the stimulation is, whether it is from masturbation or intercourse or something... else.
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