"Changing Tires" joke

[I got this from They Used to Call Me Snow White...But I Drifted
by Regina Barreca. CTM]
This couple out on a date get a flat while driving along on a snowy
night. He goes out to change the tire, but doesn't have any gloves
so before long he comes back in, job half-done, with blue hands. "Put
your hands between my legs to warm them up," says she. So he does,
and goes back out to the flat tire. It's so cold, he has to come back
in one more time to warm up his hands, again at her invitation,
between her legs. He finally finishes the job and comes back into the
car triumphant and puts the key into the ignition.
She looks at him and says, "Aren't your ears cold?"