The foreskin is positioned on the outside of the penis. A circumcision is when the foreskin covers the glans completely, but the opening is loose and the foreskin can be easily flipped open to reveal the glans and coronal sulcus. Circumcision is when the foreskin is long but the opening is small and the foreskin cannot be flipped open to reveal the glans and coronal sulcus. In the early stages, the foreskin protects the glans from irritation, which can lead to recurrent urinary frequency. As the development gradually matures, the foreskin gradually recedes to the back of the coronal sulcus, the glans slowly comes into contact with the outside world, the glans gradually becomes larger, and it is safer and more hygienic to have sexual intercourse at this time.