Giving a rim job to some one that still has shit on their ass.
Did you see Stevie Wonder at the Democratic National Convention? He totally gave someone a Rusty Muffler.
by Kenny Young August 28, 2008
Feces left around the anus. The situation one finds oneself in when, having defecated, one finds that there is no toilet paper available.
I had a crap this morning, but there wasn't any bumwad, so I had to go all day with a rusty muffler.
by king dude January 24, 2005
what my dad says after fucking my mom in the ass
damn kid, your mom sure does have a rusty muffler
by Matt January 09, 2004