How can you give yourself a cuncussion?

You are you kidding???? Why would you want to do that? I mean, I'm an expert at that, I hit my head on walls and tables and Windows every day, but still, why do it on purpose? I guess you just have to fall down or trip and try to hit your head without breaking the skin- you also could try to keep your head really close to a window when you're riding in a car and hit it on the window on a big bump in the road (I learned that from experience). Good luck???? ;)