Sit up straight in a chair with a belt around your thigh.
With your legs and feet hips width apart, the belt should be positioned around the end of your thighs, just above your knees.
Ensure the belt is secure with your legs in this position.
Keeping your back straight, tighten your abdominal muscles, then try to push your thighs out to the side into the belt.
Keep your feet in the same position.
You should feel the muscles in your buttocks, particularly on the outside of your hips tighten.
Hold this position, relax and then repeat.