Your probably just getting a little steeze lean going on. But for you to go corked your droping a shoulder somewhere. Its either in your set or once your in the air.
For your set, make sure you attact the jump. Remember even though you're spinning you have to counter the kick of the jump by getting your weight forward on the take-off. If you get lazy and let your feet ride a little bit up on you you'll go corked. Also in your set, if you throw your spin and your arms aren't thrown level it will make you dip. So try not to drop your hands on the set, and throw across your body.
Once your in the air mainly just make sure you don't dip your shoulder on one side. This happends lots when you get into your spin. Make sure you look across your body this will keep your shoulders straight and square which will prevent you from corking.
If you have footage, I can tell you where exactly and how your going into the cork, just pm me with the web addy