I am tired from the week and I really can't get a good look at the videos from turning my head sideways. Re-read the post I made above this and give what I said a try. Do what works, ignore what doesn't.
Originally Posted by ignatzami
Here's how you make yourself an instant gym-buddy to "watch" your form:
Get that low box to squat to parallel to like I mentioned above.
Before squatting, hell before doing the prone rockback get some athletic tape or even masking tape and tear off 2 strips. Stand up as tall as you possibly can; imagine yourself being pulled apart at the top of your head and at your tail bone. Keep that same posture and place the tape in 2 strips or an x across your low back where it can tuck. Go squat. You'll feel it tug at your skin or the tiny hairs if you change your position.