yes! I used to do this, very badly in fact to try to get through blocks. it releases the tension when you get the pain so it gives temporary relief, but it's a really really bad habit. I would be in pretty bad pain for sometimes up to a week after a bad block followed by a chomp on my gums. It's a secondary behaviorism for sure. I started doing it because it seemed to be a way to release the block, but I started focusing on really not doing this even if it meant stuttering for slightly longer and I think my speech has improved overall by trying to do away with this nasty bad habit. Good luck!