butt buffer-zone

Refers to the distance between Uranus and the outer perimeter of your butt-cheeks, in terms of how far an accidentally-released blob of poop has to "travel" before it reaches --- and subsequently soils --- your clothing and/or whatever surface that you happen to be presently sitting/lying upon.

Many people think that having a huge flabby behind in undesirable, but it can actually be an advantage if you occasionally suffer from liquid farts, since it provides you with a greater butt buffer-zone; this is especially fortuitous if you happen to be sitting or reclining at the time of said unexpected discharge, since it is exhaustingly more laborious to properly sanitize a seat-cushion or mattress, whereas soiled clothing can usually just be soaked in detergent-solution and then tossed in the washer.