Stage fright

So, let's talk about pee shyness (ladies, it happens to dudes sometimes, it's a physiological thing, there's a chapter in Cryptonomicon, don't make out like your plumbing isn't weird). I've heard that doing simple math in your head helps, but I've been wondering if you'd get in to a situation where you'd have a Pavlovian response, like, you're in a restaurant, and you need to calculate the tip, and you wet your pants... FAUX PAS!