Originally Posted by Tom Yum

The basic idea - you've pulled guard, get a tight overhook on your opponents right arm (if you can get him to plant his right arm by trying to buck him), place say your right knee on your opponents mid section facing to the left (like holding a thai knee kick position) adjust your hips - your hips will almost be facing the direction that you want to roll.

In one single motion, roll your opponent to your left by pulling in on the overhook and simultaneously thrusting leftward with your right knee, firmly planted in his midsection.

I've taught one of my 130-lb girlfriends to do this succesfully while in her guard.