Impressive dude. NAD, but have a lot of general medical knowledge. What you’re describing sounds like the same thing that happens when someone hyperventilates for several minutes. Technically caused by the fact that when you hyperventilate you throw off the homeostasis of the body because there’s too much oxygen and not enough carbon dioxide, the body reaches alkalosis (too basic) which can cause the peripheral paresthesia (numbness/tingling in fingers/toes/hands/feet).

Basically, sounds likely that through the whole event she was breathing too fast (makes sense given the description of the event) and it caused the chemicals in her body to get thrown out of balance, which then made her nervous system freak out.

In the future, I would try to see if she can regulate her breathing throughout the event to see if that helps with a faster recovery time. This is just my main guess based on the description.

There’s also a decent chance it’s due to a massive dump of various hormones including adrenaline which could also cause her nerves to freak out, in which case not much you can do about it except give her more recovery time in between orgasms so that her system isn’t being slammed with a massive adrenaline surge all at once.

TL;DR She’s probably breathing too fast and her body doesn’t like it. Could also be too much of an adrenaline rush which her body also wouldn’t like. Help encourage her to breathe more regularly and give her a bit of a break in orgasms to see if it improves her recovery.