well if you are sliding off too early on one side, just try to correct that. If you are ending up on your tails, either come into it more from the left, or somewhat carve in, and visa versa. Perhaps when you're tring to spin, your body could be drifting. I know that if i am spinning on, I will drift to the right, so I have to compensate for that, so keep what you are doing into consideration.
oh and make sure you are spinning 270