I came from a long line of people who didn't wear underwear. Not because they were trying to be overtly sexual, they were just poor working-class people who didn't spend money frivolously.....unless it came to booze.
My mother put us in shorts under our skirts, but never panties.
As far as I knew, nobody had a name for it. The first term I ever heard was 'sans panties' and it was in an old boyfriend's Playboy magazine.
I never heard 'commando' until I watched "Friends" and never heard of free-buffing or free-balling til I discovered this site.
My personal preference is simply 'sans' or 'commando'. To those in the know, the terms are completely understood, though I guess everybody knows 'commando' these days.
I guess they didn't talk about it, because they didn't consider there was anything to talk about.
Since neither my husband or I have worn any in years, we don't call it anything.