Pee like a racehorse

Posted by Ooga on March 09, 2003

Someone please, please tell me where this phrase is from. I have a habit of holding in my pee (I know bad for my kidneys AND way too much information) and every time I make a run for the bathroom my friend swears that she once knew the origins of "pee like a racehorse". Of course now she has forgotten it. Help?