This is where the foreskin is too tight to pull back over the head of the penis. It can cause pain or loss of sensation during sex, and can tear during sex. If not cured by skin stretching exercises it may require a small operation (circumcision).
This happens when a tight foreskin gets stuck when it has been pulled back over the head of the penis. This causes pain and swelling, as the blood flow is restricted. Usually squeezing blood from the head of the penis for a few minutes will reduce swelling enough to allow the foreskin to be pulled forward. If not medical assistance will be required. Circumcision may be required to prevent this happening again.