Sit with your back against the pad and the outside of each knee against the machine's pads, legs opened to whatever stretch feels manageable. Squeeze your knees together by driving through your inner thighs until the pads meet in the middle, then let them open back out under control. Keep your lower back flat against the seat rather than arching to help the movement along — your inner thighs should be doing all the work of closing your legs. Resist the pad on the way out just as much as you push it on the way in.