The name given to the sensation a man feels when he has not released his ejaculate or has been teased into a point where very horny, yet not be able to take care of it or "get off."
The skin on the scrotum can sometimes turn to a purplish-blue color. The condition may also occur due to 3 or 4 ejaculations over a short period of time.
However, there is a more serious condition that appears to be blueballs due to the swelling involved, this can be attributed to venereal diseases such as gonorrhea.