A sadly departed colleague of mine used to crank out some real swamp gas belters....you knew if he,d been on shift earlier as at the time the trucks we used were Lazers with cloth seats and when you sat down the swamp gas was reawoken. Nice! On another fragrant note a trick we used to play years ago on certain crews was to put a fish behind the heater grill in the saloon in winter...much merriment and green faces!!