look up any word, like dirty sanchez:
 
1.
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
 
2.
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
 
3.
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
 
4.
Used as a code word over the phone when talking about marijuana cigarettes, joints, reefers, doobies, chongers, etc., etc....
Hey man do you got any rusty mufflers?
by stoner July 17, 2002