Hitting your funny bone can cause a very unpleasant sensation. Some people feel pain, others feel an uncomfortable tingling from the elbow down.
You’re right, the funny bone isn’t a bone, but a spot where your ulnar nerve is exposed in the elbow. The ulnar nerve reaches from your collar bone down your arm, passing through your elbow. When you hit the little nook in your elbow, you actually hit the nerve which is then compressed and reacts, causing the pain or unpleasant sensation.