Not often, but occasionally, I coach my clients on how to behave in front of the judge. It depends on the client, the judge, and the situation.
I always coach a client for trial. How to dress, where we'll sit, what will happen.
There are certain judges that expect a higher level of decorum than others. When I get a sense of that, I'll quickly remind clients "If you talk to her, you say 'Your Honor,' if she talks to you directly, look at her while she's talking." That sort of thing.
Some clients need coaching, some don't.
Sometimes I coach a client as we go. I'll have to lean over and whisper "Don't cross your arms," when a client crosses his arms across his chest or "say yes or no," when a client answers a question with "uh-hunh."
But never, ever, would it have occurred to me to remind a client "Don't tell the judge to kiss your ass" or "Don't moon the judge." It's a good thing, then, that I didn't represent this client.