HOW: Start on your hands and your feet, have your hands positioned under your shoulders. To begin the exercise, assume a high plank position, while keeping your body straight lower your chest down towards the ground as far as you can, push up to the starting position. As you push up to the starting position, reach laterally to one side with one hand and lower down directly into the push up. Then return to the middle, and then perform the reach and hand movement in the opposite direction. Repeat
FEEL: This should feel like an upper body workout, your shoulders, chest, and triceps. You should also feel your core and your glutes/quads working to maintain a straight body from your heels to the back of your head.
COMPENSATION: Keep your body in a straight line, don't hike your hips high in the air or let your butt sag to the ground. Stay evenly balanced through both arms as you lower down and push up.