First of all i'd like to say good work, I know how hard it can be to get the hang of poles, I'm in the process of teaching my boy how to actually do them - he jumps them like a spread!
A lot of the time your hands are down quite low, if you pick them up a little, you'll be able to pick him up more. This is also contributing to you getting inot a bit of a chair seat over the jumps which in turn is confusing him as to whether you really want him to go over the jumps or not.
That's all I can think of for now, and GREAT job on staying on when he stopped - are you sticky taped to that saddle or something??? lol
Eventing, the sport where you strap your medical information to your arm.