This term refers to the rumbling you get in your belly after eating bad food. If you feel the "thunder down under" you should immediatly find a toilet as it usually results in an involantary explosive release of the bowls.
Oh my god, I ate some bad chinese food and am gettin some thunder down under. I don't trust my farts right now....I need to find a bathroom...FAST!
by cheesypuuf January 29, 2009