Top definition
An oily, malodorous substance found in the folds and cracks of one's butt. Typically found after a hasty wipe and/or following a rigorous workout routine. Similar to butt cheese or duck butter. Could also be a prime ingredient in the making of truffle butter.
Noun: I itched my butt and retrieved a healthy dollop of Rump Grease.

Verb: My girlfriend Rump Greased my driveshaft. I had to take an immediate shower. It itched for a week.
by Doc184 August 08, 2016
Get the mug
Get a rump grease mug for your cat Paul.