Frogs were once thought to not be able to throw up. Believe it or not, it was discovered on a space mission that they in fact can throw up. They actually vomit out their stomach and it dangles from their mouth. The frog then uses its forearms to clean out the contents of the stomach.
Then it swallows the stomach back into its body. When they hibernate, they need so little oxygen that they breathe through their skin. They also absorb water through their skin. So, they never actually drink water.