Maybe you need a confidence boost. Go find some short assed ballers who suck bad and then practice dunking on them

Do this often until you build up enough arrogance to try it on bigger and better players.
Or just practice by yourself until it becomes 2nd nature.
__________________
Height 5'7 Reach approx 7'0
BW @ 23 Jul 08: 145lbs (>13%bf)
Re-training start: Jul 08 (post injury+3 mths rehab)
Vertical Training Forum:
www.theverticalsummit.com