If I'm not Photoshopping, playing any emulators, or am not typing, then my left hand is either in my lap, in my pants (that's where it sleeps), holding my phone, or touching my face. Or a combination of any of those four!

edit
I've also picked up the habit of reflexively pressing Caps Lock when I'm done typing. And then turning it off when I want to continue.

*presses Caps Lock*