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When your standing there doing a piss and you feel a fart coming on but instead you shart yourself and now you have to sit down on the toilet to finish your shit whilst cleaning up the mess in your undies.
mate, why were you in the toilet so long?

I went in to do a piss and ended up cleaning myself up, bloody done a number 2.5 (two and a half)..
by Wayne-Car May 12, 2017
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