Sorry for the weird title, I’ll explain it better. I’m reading a book in the Warhammer universe where a character joins a “lodge” which is essentially a fraternity where soldiers of all ranks go to take off their uniforms and talk and interact without fear of retribution and without having to worry about chains of command. There’s senior staff intermingling with rank and file grunts freely and they can speak their mind without worrying about being court martialed or punished.

Is there any record of something like this ever being a thing in an actual military, where active servicemen can interact with informality amongst each other, regardless of rank?