Completely normal, it’s a form of sensory seeking because they like the feel/sound of it or because they know they get a reaction from it or even teething! It’s nothing to worry about just try and redirect his hands when you see him doing it x
Normal! Mine did this around 11 months old for like a week or two. I think she was just testing this new sensation to see how it works. Recently she also hit herself with an object repeatedly but with the same intention.
Hey hun, my 4 year old almost 5 has done this since I can remember but to me it looks as though it’s only when he’s excited or playing rough xx