Another way of saying one is
pooping.
Since it takes roughly around 7-10 minutes to
run a mile, to "run a mile" can be used for "pooping" instead of
blatantly saying one is pooping.
One can also say "2 miles" for roughly 20 minutes of pooping and so on.
Guy 1: What are you up to this morning?
Guy 2: I think I'm going to go "
run a mile".
Be right back.
Guy 1: Alright, I just ran my 3
miles this morning.