How do you lunge in Halo Reach on Xbox 360?

ah sWord canceling... hit X and B or the Right trigger at the same time to cancel your attack's damage. also - have an empty rocket launcher and a sWord... be really far from an enemy, but close enough that the rocket launcher's reticule still turns red. then hit Y and R quickly in succession and move back and forth a little... you should fly twards the person, but not hurt them. useful for getting to high places or joining somebody quickly.