HOW: Grab a band and place it behind your shoulder. Grip each bend of the band in your firsts. Next, go to a wall and start with your entire forearms against the wall. Push into the wall with the pink side of your hands as well as your elbows the entire time. Slowly work your way up the wall. At the top, lift your hands away from the wall for a few seconds. With the lift off, you should feel the muscles in your back. Think of putting your shoulder blades in your opposite back pocket. Then slide your hands back down. Repeat.
FEEL: You should really feel the muscles under your armpit working as your push into the wall. Additionally, you should feel your back muscles during the lift off.
COMPENSATION: Do not let your back arch. Keep your core engaged the entire time