Meaning of しょわー


In the last panel at the bottom of the page, she says 「しょ__ー」.

I'm not quite sure as to what that last character is, including its use(s) and
pronunciation(s).

I have seen this character in various other comics, and I think that it might
be a sound effect/onomatopoeia (?).

![image with text I can't read](https://i.stack.imgur.com/8WQuP.jpg)

What is it and what does it mean?




> しょわー

I think it's an onomatopoeia of the fizzing sound from soda.

