A doctor had the reputation of helping couples increase the joy in
   their sex life, but always promised not to take a case if he felt he
   could not help them. The Browns came to see the doctor. He gave them
   thorough physical exams, psychological exams, and various tests, then
   concluded, "Yes, I am happy to say that I believe I can help you. On
   your way home from my office stop at the grocery store and buy some
   grapes and some doughnuts."
   
   "Go home, take off your clothes, and you, sir, roll the grapes across
   the floor until you make a bulls eye in your wife's 'love canal'.
   Then, on hands and knees you must crawl to her like a leopard and
   retrieve the grape using only your tongue."
   
   "Then next, ma'am, you must take the doughnuts and from across the
   room, toss them at your husband until you make a ringer around his
   'love pole'. Then, like a lioness, you must crawl to him and consume
   the doughnut."
   
   The couple went home and their sex life became more and more
   wonderful. They told their friends, Mr. & Mrs. Green that they should
   see the good doctor. The doctor greeted the Greens and said he would
   not take the case unless he felt that he could help them. He conducted
   the physical exams and the same battery of tests.
   
   Then he told the Greens the bad news. "I cannot help you, so I will
   not take your money. I believe your sex life is as good as it will
   ever be. I cannot help."
   
   The Greens pleaded with him, and said, "You helped our friends the
   Browns, now please, please help us."
   
   "Well, all right", the doctor said. "On your way home from the office,
   stop at the grocery store and buy some apples and a box of
   Cheerios..."