This is how it works: The foreskin is cut away from around the coronal groove's rim. As the foreskin is pulled back, the edges of the foreskin are pulled back. They are tied off with stitches that dissolve over time or with diathermy, which is when an electric current is used to heat the ends of the blood vessels so that they can be tied off. The edges of the foreskin are sewn together, which makes them stronger.