Brooks Nader might wanna log off and lie low … because her ex, Gleb Savchenko, just went nuclear with a mortifying sex confession.

Gleb dished all to Dakota Mortensen on YouTube’s “Unwell Winter Games” as they were bonding over “crazy” exes … when he casually crowned Brooks the worst sex of his life!

He didn’t stop there … claiming she was so full-on, all she wanted was make-outs and choking — which he made very clear was not his vibe.

Now here’s the twist — Gleb’s mostly kept quiet while Brooks did the talking on their messy, on-off romance … spilling everything from their day-one hookup on S33 of ‘DWTS’ to accusing him of cheating.

But clearly, he had this one bomb he’d been sitting on — and yeah, safe to say, this just took a sledgehammer to Brooks’ man-eater rep.