Paraphimosis is entrapment of the head of the penis in a tight band of foreskin, which usually occurs with a penile erection in a man suffering from phimosis (narrow opening in foreskin). The tight foreskin becomes painfully trapped behind head of penis after an erection has subsided.
The problem may be solved by manipulation of the foreskin back over the head of the penis by firm pressure, or surgically cutting the tight band of foreskin around the head. Circumcision may be necessary to prevent recurrences. If unrelieved, permanent damage to the head of the penis may occur.