It varies a bit.
It’s a neurological issue, but there’s a definite psychological component; they get worse if I’m stressed, or startled, or self-conscious about being observed. And they move around; at the moment I’ve got the arm-flick, a tendency to jerk my chin to the right, an occasional tongue-cluck and a stutter (that one sucks; I’ve never stuttered before, and I’m a highly verbal sorta person).
Previously, I spent six months where my head would always be twisted down and to the left onto the palm of my hand (kind of a Rodin’s The Thinker pose, but left instead of right and on the palm instead of the back of the hand) unless I was making an active effort not to do it. My hand still tends to drift up to under my chin when I’m distracted.
The really sudden ones like the arm flick are kind of like a patellar reflex (knee-jerk, the classic doctor’s office one); no warning, no sense of volition, but nothing too freaky. It doesn’t feel like you’re a marionette or anything.
Most of the time, though…you know how when you’re going to bed, you try to get yourself into a comfortable position, but there’s always that one last semi-involuntary wriggle before you’re properly comfy?
It’s kinda like that, except that you never, ever get comfy.
