这是什么？
The foreskin is the loose skin at the head of the penis. The foreskin usually won’t pull back at all at birth. By age 15, most boys should be able to pull back their foreskin. Pulling back the foreskin stops urine from building up under the foreskin and which can cause an infection.
Sometimes males will not be able to pull back their foreskin, this can be normal. However, if the foreskin is pulled back it can become swollen and stuck. If this happens, you should seek medical advice straight away.
It is important to look after your child's penis and foreskin to keep it healthy. This will prevent redness, pain and infection.