We used the same technique. Wrap your poncho and poncho liner around you, with your head out side and a good seal around the neck, and leave a vent at ground level. Put your heat source inside, between your feet. You can also dig a hole and burn a fire in it until you have a good bed of coals. Cover it with a few inches of dirt and sit over it wrapped in your blankets. The heat will dry you out and warm you up.