Runners bum 

When you need to shit whilst running and you must clench your asscheeks to hold it in.

- "Hahaha Paula Radcliffe shat herself mid race", "ah, we've all had runners bum"

Runners bum by Mahoganay October 28, 2013

Runner's Bum 

The phrase used to describe running whilst needing to excrete one's bowls, the sufferer then has 2 choices:
- clench their arse and hope for the best
- shit their pants

"Paula Radcliffe shit herself in the marathon", "oh yeah we've all had runner's bum"

Runner's Bum by Mahoganay October 12, 2013

Bum Runner 

A drink made by someone homeless, or soon to be homeless, combining at least 10+ different drinks that have been removed from a garbage can in a party district.

Also known amongst the homeless community as a "Sidewalk Sleeper", this is semi-common activity in Bourbon Street, New Orleans, LA.

The homeless guy made a Bum Runner on Bourbon Street as tourists laughed and photographed him in the act.

Bum Runner by Brandon "Batman" Green June 15, 2011