Grasp stirrup and straddle bench orientated with side facing medium height cable pulley. Sit with feet on floor. Hold onto stirrup with both hands with arms extending out straight toward stirrup.
Keeping arms straight, rotate torso to opposite side until cable makes contact with shoulder. Return to original position and repeat. Continue with opposite side.
Slightly squeeze legs on sides of bench to prevent shifting. Bench should be far enough away from cable pulley so cable is taut when stirrup is turned back toward cable pulley. See side view and Spot Reduction Myth.