Took a look at it. Grammar is good. Spelling was good. I had no real problem following the scene. Made notes on the parsers you were looking for.
If I had a comment (and this is just my thoughts, others can certainly agree or disagree or not care): I think Byvernia got a bit too submissive and needy and adoring and cuddly in the scene. You did a good a job of getting her personality in there, and notes on her scowls and attitude, but it just seemed to all collapse at the touch of Champ's penis basically. Granted, it's a hard balance, and it doesn't mean she can't like it, but having her turn to a cuddly, lovey-dovey, begging woman so quickly just didn't feel right (in my opinion).
Following on that premise, you make mention of her pussy being wyvern-venom trained and such, but it doesn't ever translate to her being resistant or able to edge or hold out longer. As a wyvern huntress, she's exposed to the venom a lot, and no one's saying she should be immune, far from it, but she should have tolerance or experience at fighting it off (until she wins and then fucks their brains out). Here, you mention it, but only in a way that makes her more aroused and easy, not in a context of someone able to resist such lusts.
I also would have liked some mention of how the Champ may be affected, if even only a little bit or in passing. If you're going to mention that her pussy is puffy and wet and ready from all the wyvern venom she's encountered, you could at least have a line about for the Champ, even if it's only hinted.
'You can feel the building arousal as she clenches her muscles. Is she that in control, or is there some lingering traces of wyvern-venom suffusing her snatch that's causing you to pant and grunt in response'.
It's short enough that I think a reviewer can get to it quick enough when you've got it polished and others have commented.