NBA Street V3 Dunking. I can't do it!

I must fundamentally not understand the controls to this game so someone help me out here.

I can do normal dunks no problem. I hold the shoot button and they fly in to the hoop and put it down.

But I can’t use the trick stick when dunking. I don’t even see how its possible. I have to hold the shoot button on the right face of the pad. And then SOMEHOW I’m supposed to also move the trick stick to do cool dunks?!? How can I do this? If I let go of the shoot button to hit the stick with my right thumb he changes to a lay up!!

Can someone explain this to me please?