(
Australian): Underpants.
Derives from Sydney Rhyming
slang, "Reg Grundies = Undies", which is a reference to that excellent Australian
TV production outfit Reg Grundy, behind such televisual classics as Neighbours, Home and Away, The Sullivans, etc.
From "The 12th Man Again", wherein commentator Max "Tangles" Walker discusses the perils of prolonged bouts of commentating on international cricket competitions:
"when you're sitting around in the commentary
box for this length of
time, it's not unusual, really, for the old cods to
maybe nod off, get a bit numb; I think the best thing to do in situations like this is to get up, stretch the old legs;
maybe even try to casually slip the old hand down and,
maybe, give them a bit of a rub; probably try and adjust the old reg grundies while you're down there; try and loosen them up a bit. Anything, really, to try to get the old circulation going again."