right advice to my partner I think

[SCBroncos]

I've seen a veteran official in my association use this mechanic effectively, but he stopped the game to warn a player, not a coach, and he did it after a made basket when his team was inbounding the ball so as to not disrupt the game.

I don't think I would stop the game to warn a coach, especially if I was not a familiar official to that coach. I'd either T him up if it was warranted or wait for a stoppage in play and then let him know that I have heard enough.