Your toes are your friend. Your best leverage is created with the balls of your feet on the pegs. Be aggressive with the weight you're placing on the pegs in corners. Active swift fluid movements will do wonders for moving the bike. Time your movements with the rebound and compression of the suspension.
While I am not currently undersized for a bike I can relate. I rode a bike that was always one size too big so I could grow into it. You'd be amazed at how active you can be bouncing all over the pegs with your feet and still keep the bike in control. When you antcipate a buck the plan by putting some counter motion in the pegs. For instance a 2inch slick pine root would kick the rear every time on me. I would literally move my feet a couple cm off the pegs in anticipation. Then instead of having the bike rebound with me along for the ride it would instead meet my boot and body weight and counter act the entire kick.
Good luck dude.
P.S. Dogfish I always pictured you as an average build t-ball dad from the 80's with a red and white can of budweiser and a smile.
Edited by motoxhead, 20 June 2012 - 06:44 PM.