My dog loves to wear Harry Potter glasses. I'll hold them up and say, "You wanna wear your glasses, Traf?" He'll come over to me and sit patiently while I put them on, wagging his tail. Then he'll run around to everyone in the room to show off or, if I'm holding a camera, pose. After a few minutes, he'll daintily paw at the glasses and that's my signal to take them off.