2 Part Technique - There are no foolproof sweeps, so your opponent will always have a chance, albeit slim, to correctly post against your attempt; with that said, make sure you keep tight on the posting limbs you choose to check so that you can anticipate his reaction. Blocking the elbow as you perform the Hook Sweep from Butterfly ensures that he will use his foot to stop the sweep. Enter into the space he creates underneath his base to form the X-Guard for the X-Guard Takedown Sweep. The key to this sweep is to keep your head high as you technically stand, making sure his knee stays captured tightly throughout. If his knee does begin to slip free, either pull him back into X-Guard again, or jump to catch his back.