I'm curious about "boots & suspenders", searching for that gives a lot of porn results! Is this really an idiom in the US, or should it be "belt & braces"? (b

I'm curious about "boots & suspenders", searching for that gives a lot of porn results! Is this really an idiom in the US, or should it be "belt & braces"? (braces are what you call suspenders, what we call suspenders is the waist garment that secures stockings for the ladies)