"Mommy, may I please wear your [points at own head with my ear warmer already snugly atop it]? Cause it fits. Our heads are the same size!"
(Actually no, I don't have a pinhead, though hats are usually too big for me; and no, my 5 year-old doesn't have a pumpkin head, though she does have a pretty big squash.)
Pause. Can't think of reason why not. "Sure, go ahead."
It's not as if I have any cool clothes she'll ever want to borrow. Might as well let her wear the fleece ear warmer before it just embarrasses her.