"Well, it was like this", said the man. "I was having a quiet round of golf with my wife when she sliced her ball into a pasture of cows." 

"We went to look for it and while I was rooting around, I noticed one of the cows had something white at its rear end. I walked over and lifted up the tail and sure enough, there was my wife's golf ball.......... stuck right in the middle of the cow's butt. That's when I made my mistake..." 

"What did you do?", asks the doctor. 

"Well, I lifted the tail and yelled to my wife, Hey, this looks like yours!"