this used to happen to me. You have to pull it in during the second half of the trick, it works for me. And only release your hand for a short period of time, not for long, it keeps the scooter more under control.
jump off the ramp, level out, jump off the scoot, bring the scooter up then throw forward. and land. dont make the mistake of bring your inward back then forward. up,forward. practice lots and you'll have em.
throw your feet out like you're going to catch the deck. Because before I learned them I would kick it mad hard and my feet would go way back and I wouldn't re-adjust. George Louis (who can do them flat) told me to throw my feet out way in front of me to land them.