What do you fiddle with when you're thinking?

Just cut all my hair off, and I love it – except that in class and when writing, my thinking position has always included one hand twirling, twisting, pulling at my hair. This was great years ago when I had dreads, cause dreads are perfect for fiddling with and doing so locks them up further. But now, without even regular hair to mess with, I find myself pulling my new pixie cut into spikes by the end of class. So this question is especially for you antsy people with short hair – but I’m also interested in the more general answers, just out of curiosity.

Edited because of interesting and expansive answers that are popping up – Or, what do you have to be holding or touching to think, or is there a certain body position you like to be in?