T.P.
Hi,
I have a 10 month old who is doing this already but I can tell he's doing it for pleasure because we haven't taught him "no" yet. He will smile & laugh & very gently bump his head on something. Then a second later he'll do it a bit harder. He loves it. I think it's strange but I've heard of kids doing it. Hopefully, it's just a phase!
T.