Originally Posted by Saskia
For a problem like this you probably need a trainer.
Also - no one can help you with the little amount of information you provided. Its not just about stopping the behaviour - its about finding out why the behaviour occurs and changing the root of the problem.
Well put and I agree. There are any number of reasons why a horse will buck and to cure it, you first need to know why otherwise you are treating the symptom and not the problem.