Buck Muffin 

A muffin of mysterious origin, most commonly located in the vicinity of a "Pork Fritter".

Can you Buck Fuck a Buck Muffin?

It depends on how long the Buck Muffin has been sitting out!

Buck Muffin by Patrick McCloskey March 23, 2004

Backmuffin 

sarcastically saying that someone usually a male has a "nice ass" but has a flat ass but its still pretty nice and soft

mmmm you are a backmuffin

Backmuffin by buttmuffin100000 June 10, 2011