well the part you're thinking of is from the simpsons
(The Simpsons go to the opera.)
Bart: Hey, Lis, keep an eye out for the guy with the peanuts.
Marge: There's no guy with peanuts, dear.
Homer: Geez. No beer. No opera dogs.
Marge: Shh!
(The orchestra plays, "March of the Toreadors.")
Bart: (Singing) Toreador, oh, don't spit on the floor. Please use the cuspidor. That's what it's for.
(Bart and Homer laugh.)
Marge: Bart, stop fooling around. Homer, stop encouraging him.
Homer: Don't stifle the boy, Marge. We're supposed to encourage him.
Marge: Shush!
but the actual song has these lyrics
http://en.wikipedia.org/wiki/Toreador_So…
and at the bottom of this page under "media" you can find a sample of one version of the song - many people have recorded it.
http://en.wikipedia.org/wiki/Carmen