My ds is 16mths. Just last month he's started to slap himself in the head. It's not a tired thing, maybe a frustrated thing. And it's not just a slap, it's a hard slap. And not just one slap, it's about 4-5 ( I haven't counted) It can be any time of the day, in the car, walking thru the lounge - it just comes out of nowhere. He doesn't seem angry when he does it, but it's sure to hurt. I just don't know how to stop him or why he does it. Any suggestions on why he does it, or how I can get him to stop? (he does throw tantrums, but this is nothing like them)