"Show me the rule"

[Robert G]

Just finished a liitle league playoff game when the coach takes out his pitcher & as he is warming up the coach steps into the batters box to simulate a batter. I said "hold on coach I don't think that is legal & more important not safe". He says show me the rule book. Well I am not going to stop the game to look up a rule that I will probably not find. So I say I will show it to you later. He steps out a little peved & the game goes on.
What's the call?