While doing a vasectomy, the doctor slippd and cut off one of the man’s balls. 

To avoid a huge malpractice suit, he decided to replace the ball with on onion.

Several weeks later the patient returned for a checkup.

“How’s your sex life?” the doctor asked.

“Pretty good,” the man said, to the doctor’s relief. But then he added, “I’ve had some strange side effects though.”

“Whats that?” the doctor asks anxiously

“Well, everytime I piss, my eyes water. When my wife gives me a blow job, she gets heartburn, and everytime I pass a hamburger stand I get a hard-on!”