An old couple in their seventies goes to the same doctor at the same time for an annual check-up. The Doctor examines the man first and finds he's in good health and asks if he has any questions.
"Well, Doctor, I have a question about my sex life with the missus. Seems like the first time we have sex, I get all hot and sweaty, but the second time we fool around I get the chills and feel too cold to perform."
The Doctor thinks about this and tells the husband he'll talk to the man's wife first before he figures out what he can do.
The wife gets her physical examination, and she, too, is in good health. The Doctor then brings up her husband's concerns.
"He says that when you have sex for the first time he feels rather hot and sweaty and the second time he feels cold and gets a chill. What can you tell me about this phenomena?'
The wife rolls her eyes and replies, "That idiot! He feels that way because we only have sex twice a year! The first time it's in July and the second time is in December!"