HOW: Stand in front of a tall surface like a countertop or table. Place your hands out in front of you and then squeeze your stomach muscles. Your goal is to slowly bend forward until your hands touch the surface. Bend forward by squeezing your stomach muscles and trying to roll your vertebrae downwards. Once your hands touch the surface, try to push the surface down even more by using your stomach muscles, not necessarily your arms. Return back to the starting position by squeezing your glutes and hinging back. Shown in this example is a tall surface. The goal is to find as tall of a surface as you can that is right above the point when you have pain bending forward.
FEEL: You should feel all the muscles in your stomach working very hard to bend your back forward towards the object. You will also feel your glutes when you return back to the starting position.
COMPENSATION: Your arms are only there to transfer the force from your stomach muscles to the object. Try not to actively push with your arms.