What does this grinning gesture signify? The gif below shows Noriko from minute 11 of GunBuster's episode 3.



This is the dialogue directly preceding it:


  Noriko: I should at least memorize basic space manoeuvring patterns. [...]
  
  Smith: All that stuff is useless in real combat.
  
  Noriko: Why do you have to keep patronizing me?
  
  Smith: 'cause your such a cute little freshman.
  
  Noriko: I'll have you know that Onee-sama and I are the best
  team in the entire Top Squadron! A "solo" like you with no partner
  couldn't possibly appreciate everything we've been through together as
  a team. So long!


In terms of usage it seems somewhat interchangeable with the Eyelid pull taunt. I assumed it is meant to show defiance, kind of like baring one's teeth but in a more cheeky way?

The sound she makes is "bi-" I would say, but her action doesn't really fit any of the common uses of that onomatopoeia which I'm aware of. 

I feel I've seen this before but I couldn't find it among any of the teeth and smile realated tropes on tvtropes.

So, TL;DR, does this have a name, is it repeated throughout anime and signifies something particular or is it just Noriko being random and I'm overthinking it?
My understanding of it is basically that they are making a face, except it's different to how we usually know it. These are how they do it nowadays:




They are all making a face and saying "bi~". It is exactly the same as how we make a face, but Japanese style. I don't have research evidence to support this, but I have consulted quite a few Japanese people who lived in Japan for quite a while and they all agreed to my statement, so I do think it's very reliable.