...a young couple go up to the mountains for the weekend.  The guy goes out to chop some wood.  He comes in and says "my hands are freezing!"  His girlfriend says "here, put them between my thighs."  And it warms them up.

After lunch he chops some more wood.  When he comes back he cries "my hands are so cold!"  The girl says "here put them between my thighs."  Again, it warms his hands.

After dinner the guy goes out to chop some more wood and again returns saying "my hands are freezing."  At which point his girlfriend says "for crying out loud--don't your ears ever get cold?!"