try putting it in a lower gear. Standing climbs don't work very well if you are either in to big of a gear, or there are a lot of obstacles. As monique says, CG is everything.

-Try a lower gear and staying in the saddle, but moving way forward so that the nose of the saddle is actually poking you in the butt.

-if you just feel the need to stand, get your body forward.

-a variation of the chocolate cookie thing is "boobs to the tube".

It could also be that your bike is too big/too long in the top tube. This can make climbing more difficult as it's tough to find the sweet spot.