Position the massage ball anywhere along the meaty part of your hip.
Lay the ball on the floor and put pressure on it with the desired part of your hip. Bend your opposite leg and keep your foot flat on the floor while you bend the other leg into a figure-4 position. Slowly externally rotate and interally rotate your leg while you maintain pressure on the massage ball.
Take your time and repeat the pin and stretch through the length of your hip. Perform extra interal and external rotatations over problem areas.