Starting with your right foot in your partner's biceps, shoot your left leg underneath your partner's legs. As you do this, use the control you have with your left hand on your partner's sleeve to bring yourself far underneath your partner. Next, bring your back leg in first (your knee will stay behind their hips, but your foot will weave in front, creating a classic second X-guard hook). Now release the biceps control you have with your right leg, and shoot that through so that you can get the second hook. At the same time, swim your left arm underneath their near leg. Try a really easy sweep first by stretching your partner's legs out. Once their base is wide left to right, it's extremely narrow front to back. Sweep them to the back by lowering your "knee hook" down behind their ankle.