in analogy to the torture method of waterboarding; it means having to sit through the mind-numbing, nerve killing, boring recounts of some turd you cannot walk away from for diplomatic, social reasons or just out of respect.
John Stewart (The daily show):
So how did John Kerry convince Karzai to change his mind. Oh I know: listening to John Kerry go on and on, tat's like waterboring.
A waterborne stool is a stool passed in a running stream, ones podex is facing downstream and the water gently eases the stool out leaving no messy post stool detrius, the stream acts as natures midwife
Look mom, whats that bobbing downstream ? "looks like a 'waterborne stool ' to me son "