Profile for copyace

I just saw the national touring company in Chicago and loved the play, but this one seems to be over my head:

(referring to writing a note to the character Doctor Shuffhausen)
Christine: Should I use an umlaut?
Freddy: No, you smell great!

It would make sense if umlaut rhymed with douche or perfume, but both are a stretch. What word does Freddy think she's saying -- or am I overanalyzing this and the point of the joke is that he's totally clueless?