Tale of two Swaggies

Two swaggies (Tramps rrich) walking along a bush track, one says to the other " Have you just messed your pants?" "No" says the other. A few minutes go by and the first swaggie says "Are you sure you haven't messed your pants?" "I told you I haven't" the other replies. After a few more minutes the first swaggie says "Drop your pants and give us a look because I'm sure you've messed them". So the second swaggie stops and drops his pants and reveals a big lump of s.... detritus in the bottom of them. "I told you you'd messed your pants" says the first swaggie, "why'd you deny it?"
Says the second swaggie "Oh, I thought you meant today".