The Bump & Roll as it was dubbed in the video above is a great escape when opponent has the top position and is trying to punch you in the face. This is also a great technique for grappling competition as well.
As demonstrated in the video you are going to bridge or upa. By raising your hips up your opponent will be forced to put his hands on the mat above your head. If they don't they will go face first into the mat.
Next you will trap one of his arms. I usually swim my arm through to overhook my opponent's arm before I do the sweep but the way that it is done in the video will work also.
Once the arm is trapped you trap your opponents foot on the same side that the arm is trapped and then bridge over that same shoulder. They should go right over so that you land in their guard.
The guy in the video does a great job of explaining the tech going into detail.
