I just want to make sure I'm envisioning what you are saying here... your grip is over or below the penis? With the thumb to the body?
I don't know if I'm doing it correctly, but what feels the most comfortable for me, is basically a jerking-off position (thumb and index finger farthest away from the body, while middle finger, ring finger, pinky are closer to body). My thumb is matched by the combination of middle finger and index finger (thumb is fat, and I get a better grip this way). My palm is around the side of the penis, thumb over top, and middlefinger+index finger underneath. Of course, this position seems to flatten my penis, but any other position (and I generally twist my wrist during the session to alternate positions) isn't as comfortable. Palm over top or underneath just don't allow me to get as much squeeze.
Am I doing this wrong? Is there a better way?