I have a friend who pulled the whole "I'm speeding because I have diarrhea" trick. When he saw the cops lights he splashed his face with a bottle of water and held his breath to make his face red. The crazy thing is that it worked. He said that all he had to do was let out a couple of moans and the cop was like, "son you need to get yourself to a toilet quick". I wish i could have been there.