LeAnn Rimes' Healer Says She Had Natural Reaction in Viral Vid

LeAnn Rimes' orgasmic reaction to having her jaw released is totally normal ... so says the dude whose fingers were deep in her mouth.

Garry Lineham -- the internet personality and founder of Human Garage -- talked to us about the treatment Rimes shared to social media Monday ... which left her sobbing after Lineham knocked out the tension in her jaw.

Lineham tells us Rimes' reaction -- while the subject of more than a few wisecracks online -- is super normal ... the release of trauma sometimes makes people act exactly like her, bawling their eyes out in relief.

Others get real mad, and some laugh uncontrollably, Lineham says ... a huge spectrum of potential reactions, all perfectly normal.

As for how Lineham linked up with Rimes ... he says she's been trying to release the tension in her jaw via at-home exercises his company shares online -- but, she'd hit a wall. She reached out to him, and he jumped at the opportunity to help.

Lineham says Human Garage used to be a clinic ... but they weren't helping as many people as they wanted -- so, they transitioned to providing at-home material instead. He says he has received 100,000 requests just today for people seeking treatment, but he no longer does treatment for people regularly. Basically, anyone looking for the same treatment Rimes got will need to at least try on their own first.

We also talked to Lineham about why it's important for celebs like Rimes to share treatments like these they undergo ... watch the clip all the way through to hear about it.