Hey that's a great tactic, I use it pretty often to. I use usually just fake one low kick to the legs then sort of jump forward and come down on him over his guard with punches. It's been pretty effective.
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Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon: http://www.zanshinarts.org/Home.aspx,