My 1 year old has a habit of banging his head on hard surface (wall, table, bed etc). I'm having a hard time keeping an eye on him 24x7 to prevent him from getting hurt. I even tried letting him bang twice or thrice so that he'll understand that banging hurts, but he doesn't stop only. I'm worried if all the banging will hurt him long term. I noticed it's not a expression of frustration coz he does this even when his calm or playful. Is this a phase thing? Does other babies do the same? If so, what did the parent tried, that worked, to stop the banging.