After examining his elderly wife, the doctor said: "You appear to be fine.  Do you have any medical concerns that you would like to discuss with me?" 

The lady replied that she had no questions or concerns. The doctor then said to her: "Your husband had an unusual concern. He claims that he is usually cold and chilly after having sex with you the first time, and then hot and sweaty after the second time.  Do you know why? 

"Oh that crazy old coot," she replied.  "That's because the first time is usually  in January and the second time is in August."