Oh, hell, I'm always giving myself head rubs. I'm bad for it at work, when it's quiet and I'm sitting there I'll be going over things and my left hand just goes right up and starts by stroking the goatee then making the way up to the head. Just last night actually, I was sitting there focussed on some intel reports and then I felt someone giving me a head rub.
a co-worker said she noticed I wasn't rubbing my head like usual and thought she'd help so I could focus more on the reports.