I found that if the guy I rolling with a lot bigger than me (often) BUT is not very experienced, you actually can let go of your under hooks for a second and push him with your thumbs in his armpits as you whip. This is only a possible advantage if your trying to sweep with old school though, if your trying to get to dogfight then IME, you couldnt get better advise than Compella gave above. Im just starting though so I might not know what Im saying.
