I originally thought it would be funny for Ashley to describe how the process of summoning Fox looks, and for Nanase to react with "what? Really? I had no idea!"
Which would have made SOME sense... Right up until it made NO sense.
Nanase closes her eyes when casting the spell, and even if Nanase could see through Fox's eyes before Fox was fully formed, it would be from Fox's perspective. It makes sense that she hasn't seen it with her own eyes.
The problem was that there's simply no way someone hasn't described it to her before now.
At a minimum, Ellen, Diane, and Charlotte have witnessed her casting it. Even ignoring that she's undoubtedly shown it to even more of her friends (there's no way Justin hasn't seen Fox), each of those three would have commented on it.
(Okay, Diane might have been momentarily speechless, or said something unintelligible, but the other two definitely would have commented on it.)
So instead, envious Ashley and Tedd are envious (not that Ashley is any surprise in that regard).
WHICH brings up the question of whether Ashley and/or Tedd can copy this spell.
Ashley: Potentially, someday. This is EXTRA advanced.
Tedd: Potentially, someday. Tedd is good at making transformation wands, but is still working on, um... EVERYTHING ELSE. Which may or may not be interesting, what with transformation being "advanced"...