weirdest feeling in the world

I am doing physical therepy for TMJ a disorder of the jaw. Part os my PT is Ultrasound therapy or muscle stimulation. This is by far the weirdest feeling in the world. It is like being shocked while at the same time having a very lovely massage. In your Face! I have only had one session of this therapy and it was on a very low setting and for only 4 minutes on each cheek. Next week I am supposed to do double that.I ought to be twitching for a good 1/2 hour afterward. Yippee!