Knee Buckler 

-associated with an intense sensation (usually due to sense of touch) where one experiences an extremely pleasant feeling to the point where involuntary contraction of muscles occur.

-event that make someone buckle his knees

..the way she ran her hands down my hips was an absolute knee buckler

Knee Buckler by TW IN May 30, 2018

knee buckler 

An extremely good blow job.

Cathy used those great DSL'S to give me a "knee buckler" last night.

knee buckler by Eman3737 November 29, 2004

knee-buckler

An intense orgasm

"I didn't fap or have sex for two whole weeks. When I finally came, it was a knee-buckler!"

knee-buckler by Michael Michael Motorcycle August 21, 2013

kneebuckle 

Some Head so good that is literally makes your knee's shake.

That girl sheeb gave me some great kneebuckle, i almost collapsed.

kneebuckle by BasedGodisGoat October 22, 2014