Why don't men do this after they poop?

First of all, men must urinate standing up, which is determined by their physiological structure.

The male urethra is S-shaped. When standing, the urine can flow out more naturally due to the influence of gravity. However, when squatting or sitting to urinate, the urethra will become an inverted hook shape and will be compressed, causing pelvic congestion and making it more difficult for urine to be discharged. Over time, inflammation of the bladder and urethra or other health problems may occur.

Secondly, men should not rush back to their seats after urinating.

Instead, you should stand and move for 3 to 5 minutes before sitting down. This is because after urinating, the internal and external sphincters of the urethra will close, forming a closed cavity in the prostate urethra. If you sit down immediately at this time, it will increase abdominal pressure, and the pressure in this closed cavity will also increase. First, it will cause the residual urine to flow back, and the bacteria in the urethra will have an opportunity to take advantage, thereby inducing chronic prostatitis. Second, it will aggravate the original prostate symptoms, and over time, it will aggravate the symptoms of bladder outlet obstruction.