I wouldn't have put myself in that position in the first place. It never ends well. Coaches will always bring up something that happened in another game in order to:
- Test your knowledge of the rules.
- Get ammunition against another umpire
- Learn if they were wrong (rare, but there is such a thing as honesty in this world)
Anytime I'm asked about something that happened in the game, I'll do one of two things: back up my fellow umpires (if they were right), or blow off the question ("coach, I wasn't there, so I don't really know what to tell you").
The last thing I want to do to a fellow umpire is throw them under the bus. Hopefully, they will extend you the same courtesy.
If something like that then happens in your game, all you can say is "coach, I understand you're confused, but this is my call. I can't speak for the ruling from the other night, but if you feel that you were wronged by my call, you are welcome to protest."