What do bunny's drink out of?

Anywhere!

Wild rabbits drink water from ponds, streams, puddles, and the like; they also get water from the fresh plants they eat.

Pet rabbits drink from bottles or bowls. Water should always be fresh and plentiful. Bowls should be washed with soap and hot water daily. Bottles (including the sipper nozzle) should be scrubbed out with soap, hot water, and a bottle brush every 1-3 days (more frequently if you notice algae).