have an accident
1. to experience something that was not foreseen or intended. Traffic is very bad. I almost had an accident. Drive carefully. Try to avoid having an accident.
2. Euph. to lose control of the bowels or the bladder. (Usually said of a young child.) "Oh, Ann," cried Mother. "It looks like you've had an accident!" Mother asked Billy to go to the bathroom before they left so that he wouldn't have an accident in the car.