Find a tall-backed chair — such as one from your kitchen table or a desk — pad it with some pillows, and sit him down. Straddle his hardened member and lean back slightly, placing your hands on his knees. Extend your legs, one at a time, until each of your ankles is resting on one of his corresponding shoulders. Pump your booty back and forth at a speed that makes you moan. To supercharge your thrusting power, balance your weight between your ankles and your hands.