When dinosaurs wish each other a merry Christmas, they usually say, "Dino-saur-a-don! Merry Christmas!" It's a cute and playful way for them to express their holiday spirit. Dinosaur-a-don is a play on words, combining the word dinosaur with the word don, which is a way to wish someone well in many languages. So, by saying Dino-saur-a-don, they're wishing each other a happy and merry Christmas in a dinosaur-like way!