I think you're missing the essence of it. Maybe don't think of it as pop but a twang that comes from quickly and forcefully compressing the tail against it's own camber and the ground. It has to be a snappy, quick, force full motion.
You can't just shift your weight backwards. Think more about driving your back foot forward so forcefully under your hips that you worry you might fall over backwards. Roll the shit out of your back ankle right through the binding towards the tail. You will immediately discover the snap. If you don't first shift your weight out over the nose of the board you will never be able to generate enough force driving your back foot under yourself. Then use your arms, core, and everything to "get up out of the way" of the popping piece of wood.Get low, core engaged to keep force aimed down through the board, don't break at your waist, and keep your arms and shoulders parallel to the board.
Remember to think about it from a skateboard stance. "Lift" up your front foot sideways from the middle of the foot, snap the tail down afterwards in a piston motion. Stay sideways head turned board flat, hips unbroken, back straight.