After losing her last baby tooth, a young Twilight learns something about dragons from her new adopted brother: apparently, they never stop losing teeth. Naturally, Twilight and Spike decide to milk the Tooth Breezie for all she's worth. After all, the Tooth Breezie never seems to run out of bits while she can never get enough teeth, while Spike can't run out of teeth but can never get enough bits. Win-win. It's a great idea.

So why does Mom look nervous all of a sudden?