Sometimes, in this age of cultural decay, the only way to answer bad manners is with worse manners. That's esspecially true in crowds, audiences, public meetings that get out of hand.
On behalf of the no doubt decent majority of people around you, thanks for having the testicular fortitude to speak up - in terms the squirt could understand. He'd probably been told about "inappropriate behavior" all his grade school life and with no reprisals or harsh consequences to deter further incidents, it registered as meaningless - and therefore license to repeat.
Maybe, just maybe, he might back off next time, thinking "Somebody might be watching who'll..."
