Why do boys’ underwear get wet when they sleep?

Nocturnal spermatorrhea in men is a normal physiological phenomenon, which is mainly caused by factors such as natural discharge of semen after sexual maturity, accumulation of sexual stimulation, sleeping position pressure, prostatic fluid secretion, and dream induction.

1. Natural discharge of semen:

After puberty, male testicles continue to produce semen. When the seminal vesicles are full, the central nervous system triggers the ejection reflex during sleep. This kind of unintentional ejaculation mostly occurs in the deep sleep stage, and 1-3 times a month is within the normal range. It is common in sexually active men aged 15-25.

2. Accumulation of sexual stimulation:

If you are exposed to sexually suggestive information or sexual fantasies during the day and are not released, the cerebral cortex will vent the accumulated sexual excitement through dreams at night. At this time, the corpus cavernosum of the penis becomes congested and erect, accompanied by the rhythmic contraction of the vas deferens, resulting in nocturnal emissions, which is a self-regulatory mechanism of the body.

3. Sleep position compression:

When sleeping in the prone position, friction between the penis and the mattress may induce reflex erection. Continuous compression of the perineal neurovascular bundle may simulate sexual intercourse stimulation and promote involuntary contraction of the smooth muscles of the seminal vesicles. This situation can be improved by adjusting the sleeping position.

4. Prostatic fluid secretion:

Parasympathetic nerve excitement during sleep promotes the secretion of prostatic fluid, which mixes with bulbourethral gland fluid to form transparent mucus. This type of secretion does not contain sperm but may soak underwear. It usually occurs before and after morning erections and needs to be distinguished from pathological urethral discharge.

5. Dream induced reaction:

Sexual dreams that occur during REM sleep activate the limbic system and trigger ejaculation through the spinal ejaculatory center. This type of nocturnal emission is often accompanied by vivid dream memories and is closely related to fluctuations in testosterone levels. After the age of 35, the incidence gradually decreases with age.

It is recommended to choose breathable cotton underwear to reduce local moisture and avoid excessive excitement or drinking before going to bed. Frequent nocturnal emissions more than three times a week accompanied by backache and fatigue should be investigated for prostatitis or seminal vesiculitis. Kegel exercises can be performed daily to enhance pelvic floor muscle control. Maintaining a regular sex life or moderate masturbation can help regulate semen metabolism. Parents of teenagers should correctly guide them to understand physiological phenomena and eliminate shame. Pay attention to distinguish pathological urinary incontinence from physiological spermatorrhea. The former may indicate diabetic neuropathy or complications after prostate surgery.