Ear blushing feels like a whole new frontier of cute that we need to explore as soon as possible.
Great idea. The first move would be to do some historical research looking for any previously unnoticed ear-blushing pioneers--they've got to be out there.
And no ear-licking or ear-biting--that's all fine in its place (in some contexts arguably better, even classic), but much more likely to cross the Cute/Lewd event horizon. Which is also fine. In its place.