Definitions by Nelson a.k.a. HairyCheeks

wipe the sidewalls 

The action of cleaning the inside of ones ass cheeks after experiencing anal seepage.

Example 1:
Dude I think i just sharted, I might need to go wipe the sidewalls.

Example 2:
You're going to have to wipe the sidewalls after that one.

wipe the sidewalls by Nelson a.k.a. HairyCheeks January 7, 2008