2 year head banging

lsmithk2

My son started banging his head in his crib to go to sleep when he was about 18months. I know it's normal, but damn it's annoying. Now he does it at nap time and any time he wakes up in the middle of the night. He's exactly 2 today, so this has been going on 6 months. Was wondering if anyone else is going through the same thing and if you had any advice on how to deal with it or how long it will last?