I have experienced a lot of this tingling sensation during various stages of my developement. It was particularly strong and frequent for the first half of last year.
It always seemed to coincide with (what I can only call) periods of progress. As msagansk says, I also associated it with being on the right track.
Thats what I associate it with also guys! But I also get some hot tingles when i try to still my mind, or when im not thinking much at all, not unpleasant just mildly hot. Negative feedback huh, that doesnt sound right ... maybe I just need to think about my intentions then ....