Mucus

MADELEINE: (from the potty) Julia's DANCING!
ME: Julia's eating her lunch. She's not dancing anymore.
MADELEINE: She's DANCING!
ME: The music is still playing, but she's not dancing anymore. She's eating her lunch.
MADELEINE: Oh, yeah, it's da MUCUS.
ME: The MUSIC. Can you say MUSIC?
MADELEINE: (delighted) MUCUS! Not mucus.
ME: MUSIC.
MADELEINE: Yeah, mucus. Not mucus.
ME: Can you say MUSIC?
MADELEINE: Mucus! Mommy, say mucus?
ME: Music.
MADELEINE: Julia, say mucus?
ME: Julia, Madeleine wants you to say mucus.
JULIA: (giggling) Why?
ME: Madeleine, can you say MUSIC?
MADELEINE: MUCUS!! Mommy, say mucus?

I gave up.