A woman is driving and notices a police car behind her with his lights on and she starts to get nervous, planning what she will say when the officer pulls her over. The officer appoaches her vehicle and before he demands her license and registration, she chimes in, "I know! You pulled me over to invite me to the policeman's ball!"
To which he replies, Policemen don't have balls."
Upon realizing what he has said, he clears his throat, tips his hat and walks back to his car.