Have your partner lie down on the ground. Lie on top of him with a knife in hand and start to roll over him in any way you want using your body and legs to move and keeping both hands free. As you become more comfortable add slashes and cuts that are part of your body movement and if you stop moving your partner will slap or hit you in any way he can to help you keep moving as you work. Remember the person or persons that keep moving after an encounter are alive.