I had to mount a gun to get to the answer but, for me, I shoot with a slack jaw, meaning that my jaws are not closed completely and the teeth do not touch, bottom jaw to top jaw.
I try to shoot as totally relaxed as possible and, I believe for me, closing my jaw and making the teeth contact between bottom and top jaws would be an indication, or maybe more accurately a result of, tension. And that is not at all what I want to feel as I trigger the gun.
Never had but one gun slap my cheek, and it was stocked waaaay too high.
SRH
