Men's Health: A Detailed Explanation of the Stages of the Sexual Response Cycle
Male Sexual Response
From sexual arousal to orgasm, and from orgasm back to the initial physiological state, the reproductive organs and other aspects of the body undergo a series of cyclical changes; this is the sexual response cycle. The sexual response cycle is divided into four phases: excitement, plateau, orgasm, and resolution.
A characteristic of male sexual response is the ability to quickly enter a state of sexual arousal. This is related to the "active" and "aggressive" nature of male sexual desire, while female sexual desire is characterized by "passivity and receptivity." This difference perfectly corresponds to the "active" nature of sperm and the "passive" nature of the egg during fertilization. Because sexual arousal involves a wide range of psychological aspects, the difference in the time it takes for the sexes to enter the sexual arousal phase is reinforced by socio-psychological factors. Changes in sexual response are mainly manifested in changes in the reproductive organs and peripheral bodily changes. The main causes of these changes are the nerve conduction of sexual arousal and the congestion of local blood vessels.
(I) Excitation Phase
The male sexual arousal phase is primarily characterized by penile erection. The corpora cavernosa of the penis swell due to engorgement, and the tunica albuginea surrounding the corpora cavernosa is fully stretched. This pressure blocks blood flow from the subtunica albuginea veins and intersinus veins, maintaining a firm erection. This state can occur within about 10 seconds of receiving psychological or reflexive sexual stimulation, but if it doesn't progress to the next stage of the sexual response in time, it will temporarily subside and may recur upon further stimulation.
When a person is fatigued, anxious, or mentally distracted, the penis may not achieve an erection or maintain one. During sexual arousal, the scrotum also undergoes morphological changes. Due to the contraction of the cremaster muscle, the spermatic cord retracts, the testicles rise towards the abdominal cavity, and the scrotum, due to its tautness, becomes smooth. This change in the scrotum only lasts for a few minutes but recurs in later stages of the sexual response. Some men may experience nipple erections during the excitement phase, but most men do not.
(II) Plateau Phase
There are no sudden physiological changes between the excitement and plateau phases; rather, many physiological responses are further intensified based on the excitement phase. The plateau phase indicates that the physiological tension, muscle tension, and nervous tension of orgasm reach a higher intensity. At this time, breathing deepens and accelerates, blood flow to the genitals becomes more pronounced, the penis becomes erect, and euphoria is intense in both men and women. In men, the intensity of sexual excitement and tension during the plateau phase is a sustained increase from the level of the later excitement phase. Due to further engorgement of the corpora cavernosa, the penis becomes very hard, its circumference increases, the glans penis darkens to a purplish-red color, and the testes may also increase in volume due to engorgement. The testes fully elevate towards the abdominal cavity and undergo characteristic testicular rotation. During the plateau phase, mucus from the bulbourethral glands flows from the urethral opening, and in some cases, sperm can be found in it. Understanding this physiological process is beneficial for scientifically mastering contraceptive methods. Peripheral reactions include generalized muscle rigidity, further increase in blood pressure, tachycardia, and shortness of breath.
During the plateau phase, the penis gradually progresses from slow, conscious thrusting to rapid, forceful thrusting that is no longer under control, accompanied by a strong sense of pleasure. If the movements are harmonious, both partners' body movements, especially pelvic movements, will be perfectly coordinated, allowing both to reach orgasm simultaneously. Emotional communication between the two is crucial for achieving this.
(III) Orgasm Phase
Male orgasm is the period of highest sexual arousal in a man during sexual response. Scientific research shows that the human body has a threshold for orgasm; once sexual stimulation and arousal intensity reach or exceed this threshold, a nerve reflex triggers orgasm. For both men and women, the orgasmic phase is only a very short time. With the onset of orgasm, men experience a powerful pressure that makes ejaculation imminent and unavoidable. In reality, there are still 1-3 seconds before ejaculation. Due to high arousal, the thrusting force and frequency increase, and the glans penis becomes more engorged, with an intention to concentrate the body's strength into the depths of the vagina, followed by ejaculation. Ejaculation is the physiological process by which semen is ejected from the urethra under strong pressure. The range can be half a meter or more. However, with age, this range decreases, and sometimes semen may even leak out of the urethra. This is due to weakened muscle contractions associated with ejaculation, and is not a pathological condition. Masters and Johnson divided the ejaculation process into two stages. In the first stage, the smooth muscles of the efferent ducts of the testes, epididymis, vas deferens, ampulla of the vas deferens, seminal vesicles, and prostate gland contract together, causing semen to collect in the prostatic urethra. Simultaneously, the bulbourethral glands secrete fluid that joins the semen. During this period, the sphincter closes, blocking the retrograde flow of semen to the bladder. In the second stage, the impulse generated by the semen filling the urethra is transmitted via the sacral nerve to the ejaculation center in the spinal cord. Then, rhythmic impulses are sent from the spinal cord to the skeletal muscles; this causes the bulbospongiosus, ischiocavernosus, and urethral sphincter muscles to contract rhythmically, generating pressure that forces the semen to be ejected from the urethral opening of the penis. Initially, there are 2-3 contractions with an interval of 0.8 seconds, after which the rhythm slows down. The number of contractions is approximately 4-10 or more. This difference in the number of contractions reflects the intensity of the orgasm. The intensity of a male orgasm depends on the degree of fatigue, the psychological state of the sexual body, the intensity of sexual stimulation, and the interval between two sexual encounters.
(IV) Resolution Phase
With the end of ejaculation, the sexual energy is released, and muscle tone in both the reproductive organs and the entire body decreases sharply, and penile erection quickly disappears. Penile congestion and swelling also subside as blood flow returns to normal. Testicular volume also decreases accordingly. In fact, in terms of anatomical and physiological changes, the resolution phase is the opposite of the excitement phase.
One of the most significant characteristics of the male resolution phase is the refractory period, a period after orgasm when the individual is unresponsive to further sexual stimulation. The length of the refractory period varies from person to person and from time to time, but is most closely related to age. In adolescence, the refractory period can be as short as a few minutes, while in old age it can last for several hours or more. If intercourse is repeated within several hours, the refractory period will be extended accordingly. Compared to men, most women have the sexual potential to achieve repeated orgasms. Therefore, some believe that only men have a refractory period. Understanding this physiological difference between men and women is of great significance for promoting sexual harmony. Functionally speaking, the refractory period is a necessary interval for men to accumulate sexual energy and replenish sperm count to adapt to new sexual tension. This is because men expend much more energy than women during the entire sexual response process, and also release a large amount of sperm. It is precisely because of the existence of the "refractory period" that physical damage and sperm deficiency caused by excessive sexual intercourse can be avoided. It is particularly noteworthy that men with severe premature ejaculation often exhibit an excessively prolonged refractory period.