When you will feel that he again plan to do it, the last seconds,do your voice up to him and see if he a little stop think to buck you. He will understand that you know what he want next moment and he not will continue till next time. They are like small foxes very sharp)) and will use all methods)))
To teach him it need,when your pony will do the same to buck you down. Give him by his ass with whip and speak with high voice to let him listen that something you don't like when he do this. When he stop do this,continue ride on him and not let him repeat the same,Becouse he will know that again will get by his ass)) you must show that you are lider but not he.He by such way check you. Only don't fall!
They are many crazy)) arrogant and vindictive. They even can jump on you or attack somehow)) maybe some breads are good but I didn't meet till now good breed pony,if only Haflinger but they are bigger!