With my son, it's noises (humming, psh-psh! or whatever) and maybe a bit of bouncing.
I initially went through the scolding process, too. Now, I back off but pay attention. Sometimes he seems to need the fiddling to focus his mind. Last week, he whipped through a bunch of math problems, made two small mistakes in the bunch, and spent the entire time talking to himself and drumming his pencil.
That said, sometimes he's just fiddling around! Which is why I pay a bit of attention (e.g., I leave them room but peek around the corner now and then).
Val
