Two tramps met and decided to walk together. As they walked along, one trampt sniffed the air and looked around. "Er, by any chance have you shit yourself"? he asked. "No, I haven't", replied his companion, so they walked a few miles further. The first tramp sniffed the air as they walked and finally he said, "Are you SURE you haven't shit yourself". No, replied his companion again. A few miles further on and the first tramp said, "Look, I don't believe you, just drop your pants". His mate did just that, and there, in the crack of his arse was a lump of hard turd. "I thought you said you hadn't shit yourself" said the first tramp. "Oh, I thought you meant today" came the answer.