This guy goes to the doctor to get his first prostate exam. The doc puts on his glove and sticks his fingers in to take a look. After awhile he says,

"Son, I have some good news and some bad news. The good news is you don't have prostate cancer!"

The guy says "So whats the bad news?"

Doc tells him, "You'll have to stop masturbating."

"Why?" the guy asks.

Doc says, "Because it's making me nervous!"

via big ed