As I'm sure you are all familiar with, the Womping Willow is a willow that takes pleasure womping anything and everything within reach. There is a knot that a small animal/thing can put weight on to stop the branches from trying to kill you. There is also a path leading to the shrieking Shack in Hogsmeade. I must ask you all not to attempt to go through the path to the Shrieking Shack.
You can also get hit by the Womping Willow. Let's face it - you can't be lucky every time you tempt its deadly branches, can you? When you are hurt, go post in the Hospital Wing. Your friends/enemies can meet you there to jeer or help you. It's much more fun role playing this way, it keeps things fresh.