On the 2nd episode when Fry first met the Planet Express crew and got his "physical" from Dr. Zoidberg
Dr. Zoidberg: Now open your mouth, and let's have a look at that brain. (Fry opens his mouth) No, no, n-n-no , not that mouth.
Fry: I only have one.
Dr. Zoidberg: Really?!
Fry: Uh, is there a human doctor around?
Dr. Zoidberg: Young lady! I'm an expert on Humans. Now pick a mouth, open it, and say, "DOODLEDOODLEDOOOOO!"
Fry: Uh, (clears throat) "DUDDADUDDADETTADET!"
Dr. Zoidberg: (offended) WHAT?!!?! MY MOTHER WAS A SAINT!!! GET OUT!!!!!
Dr. Zoidberg: Now open your mouth, and let's have a look at that brain. (Fry opens his mouth) No, no, n-n-no , not that mouth.
Fry: I only have one.
Dr. Zoidberg: Really?!
Fry: Uh, is there a human doctor around?
Dr. Zoidberg: Young lady! I'm an expert on Humans. Now pick a mouth, open it, and say, "DOODLEDOODLEDOOOOO!"
Fry: Uh, (clears throat) "DUDDADUDDADETTADET!"
Dr. Zoidberg: (offended) WHAT?!!?! MY MOTHER WAS A SAINT!!! GET OUT!!!!!