Inadvertent

[pizanno]

I had this situation that I still don't know what I should have done:

High school playoff game. Not a tight game, but not a blowout. No problems or trash talking thus far.

2nd half, Team A starts to make a run. A1 dunks in traffic to cut the lead to 2. Excitedly, and completely without malice, A1 turns and (without seeing B1 there) punches the air with emotion, catching B1 in the back of the head (he was also turning down court to continue play).

B1 goes down. A1 embarrassingly tries to help B1, but he stays down. Fortunately, B1 not injured...more shocked. He gets up and stays in the game (after sub).

Should I have called a foul? I did not. Coach wanted a foul, I think more because A1 had four fouls and Team A was making a run. He didn't like my "incidental contact" explaination, but agreed that it was an accident.

What would you have done? Is there a rule citation that covers this weird situation?