This exercise is great for whittling the waist. As a bonus, it also works the lat, the largest muscle in your back.
Begin in a side elbow plank on your right side with straight legs and your feet stacked.
Inhale and lower your pelvis to the floor so your right hip hovers just off the floor. Exhale and press up through your right waist to lift your pelvis and return to side plank. Pull your right shoulder blade down your back to stabilize your shoulder.
Repeat for a total of 10 to 15 reps to complete a set, then switch sides. Do three sets.