How to do it: Lie on a mat on the left side of your body with your left leg bent, just slightly behind you. Extend your right leg diagonally from your hip. Wrap your left arm around your body (as seen in top photo) and bend your right arm, putting your right hand on the mat near your left shoulder.
Next, while keeping your feet on the mat and with your left arm wrapped around your waist, extend your right arm--remember not to lock your elbow!--and push your body up (as if doing a push-up). Then, lower your body back down to complete the rep.
Do 24 reps, then switch sides and repeat. Work up to 2 sets.
Try this move: Sideways Floor Push