look up any word, like darude - sandstorm:
 
1.
a. A rare genetic mutation causing severe excesive pubic hair growth around the anus.
b. An amusingly witty insult.
c. A piece of wintersports equiptment used to prodect the rump from impacts and low temperatures.
www.buttmuff.com
You sir, are a butt muff.
by Davio Grimmy April 15, 2005
 
2.
A slightly more course form of bum fluff, the mid point between chin-pubes and a beard- an essential for all younger daedo's
That daedo there, has the most over grown butmuff i have ever seen.
by Anonymous April 08, 2003