THE SETUP: T.E.N.S.E.
Laying down may entice you to relax. Don’t. Get TENSE from your toes to your traps, like a spring under pressure, with your shoulder blades planted firmly into the bench. Become immovable.
Dig your traps into the bench. Pinch your shoulder blades together and down. This will protect your shoulders and give you a solid base to press from.
Plant your feet so that your knees are below your hips and your lower body is stable. Use your legs to push your butt closer to your shoulders. This should tilt your rib cage to put even more pressure into your traps - preventing them from sliding. This will protect your shoulders and pecs, while involving more muscle and weight.
Take a deep breath into your belly and hold that breath throughout the first rep. Only take shallow, "top off" breaths at the top of each rep or two. Pressing this air down and out will help you stay rigid and transfer energy from your legs into the press.
Without releasing the squeeze in your shoulder blades, reach your arms straight up. Rotate your thumbs in toward your feet until the bar crosses the meatiest part of your palm, inline with the center of the wrist. Note the distance between your hands, then slide them apart to increase that distance by half. Wrap your fingers around the bar and squeeze it as tightly as possible. Slide your thumb one finger-width in from your index finger as if to make room for one more digit, then bend the bar apart with your lats.
Forcibly pull the bar from the rack toward your feet; pressing it upward only enough to clear the j-cups. Stop when the bar is stacked directly over your shoulder blades with your elbows locked. This will stabilize the bar and pin your shoulders.
THE MOVEMENT: P.R.E.S.S.
Pull your chest to the bar under control. Then PRESS yourself away it with vertical forearms and forceful feet.
With the weight of the bar pinning you to the bench, lift your rib cage toward the bar. This will improve leverage and stability.
Pull the bar down to meet your lower sternum. Engage the back muscles to control the bar’s quick descent. The bar should meet the sternum where your wrists are stacked above your elbows.
Drive your feet down and away from you HARD, without allowing your hips to rise or your body to move. This force will transfer through your chest, helping to drive the bar off your chest and back toward its top position over your shoulders.
Keep the wrist and elbow stacked as you press the bar back up. This will require your armpits to be open about 45° on each side. Doing so will move the bar to top position with peak force.
Imagine the bar is immoveable; so instead of pushing it away from your body, you are pushing your body away from it (and into the bench). Just like a push-up, this will track your hands from below your nipple line at the bottom to above your shoulders at the top.