The unfortunate event when fecal residue is left around the anus and the person in question does an activity which involves great exertion. This exercise leads to sweating and consequently blends with the faeces to form a substance known as 'Bum Oil'.
Dude 1: that was a great round of tennis
Dude 2: yeah dude, but we should have stopped earlier, i've got bum oil running down my leg!
Dude 2: yeah dude, but we should have stopped earlier, i've got bum oil running down my leg!
by Pretty in wellies May 31, 2007