I actually use the teeth clenching as a sign that I need a vape...did the same with smokes. I had a rigid schedule to keep from going over 1 ppd and by the end of that hour, my jaw was clenching like mad. Now, when I start doing it, I take a few drags of the pv and set it down. 
I vape far more often than I used to smoke, BUT I vape for far less time. 3 or 4 puffs on the pv every 10-15 minutes versus a full cig once an hour.
I vape far more often than I used to smoke, BUT I vape for far less time. 3 or 4 puffs on the pv every 10-15 minutes versus a full cig once an hour.