Place your hand near his head area and cup him in his hands, it's like a forced ball up. Not great for trust unfortunately but I saw it as a way of changing the fight to flight in BP's. It is hopefully just the fact that he was moving.

Best of luck!

youtube clip, comes on half way through to get the BP to ball up:

http://www.youtube.com/watch?v=S7DQssbM0uk