I'm convinced that cracking the last line is crucial to getting this one... "Mix to/Insult the young lady"

Young ladies who appear in the game:
Yuna
Rikku
Lulu
Elma
Lucil
Shelinda
Tidus
Dona
Calli

There are others, but I can't think of any who really stand out or have a significant role. Now, as for young ladies who are in some way insulted during the story...

Yuna - gets her fair share of insults
Rikku - Wakka's none too kind about the Al Bhed
Lulu
Elma
Lucil
Shelinda - she gets heaps
Dona - reowr!
Calli

And then there's Tidus' verbal sparring with the Luca Goers prior to the Blitz tournament; there are several women in that team.

I get the feeling that Blitzball is relevant to this one.

,,,But now I'm stuck again.