What is the private part of the human body?

The private part of the lower body of the human body: the urethra

A groove three feet above the ground: three inches downward from the lower abdomen.

Water flows all year round: Normal people (regardless of men and women) need to urinate every day.

No cattle or sheep are seen grazing: Normal people have hair covering the front of their private parts of the lower body.

I saw a monk coming to wash my hair: For the health of the body, it is recommended that people wash their buttocks every day.

Urethra

The urethra is the tube that leads from the bladder to the outside of the body. The male urethra is slender, about 18cm long. It starts from the internal urethral opening of the bladder and ends at the external urethral opening. During its journey, it passes through the prostate, membrane and cavernous body of the penis. The male urethra has both the functions of urination and semen. The female urethra is thick and short, about 5cm long. It starts from the internal urethral opening, passes through the front of the vagina, and opens into the vaginal vestibule. The male urethra has a sphincter composed of circular striated muscles in the membranous part of the urethra, called the external urethral sphincter, which is controlled by consciousness. When the female urethra passes through the urogenital diaphragm through the perineum, it is surrounded by the urethrovaginal sphincter, which is a striated muscle and is also controlled by the will.

Reference link: Baidu Encyclopedia_Urethra