backflirt 

The act of liking older instagram/facebook posts in order to convey romantic or sexual interest

"Omg, my crush Joe just backflirted a picture of me from 137 weeks ago! He's totally into me."

backflirt by maleducadagutfreak July 18, 2016

backfire drunk 

When you try to get your girl drunk but it backfires and she pukes all night and you can’t get a piece.

I only want a couple drinks. I don’t want to get backfire drunk.

backfire drunk by Phoenix420 January 28, 2022

Backlit

Ejaculating an unfathomable amount of cum on a human males back, typically after engaging in homoerotic activities with a male (or trans male).
The word is stemmed from the phrase "light up my back."

"Dude, how was Thailand? Did you get any of their cheap sex massages?"
"Naw dude, I paid them extra to backlit me! It was awesome!"

Backlit by Svensk och Indisk Pojke September 26, 2019

Monkey Double Backflips 

Extravagant and exotic sex techniques used by females to lock down a high value male.

She was with Thomas but he was kind of boring. So she also met with Sebastian from sales department who was making six figures, has a sixpack and a nice car. So she does monkey double backflips all over him to get herself in a better financial position if she continues this until he takes her as a wife.

Monkey Double Backflips by mstar1337 July 15, 2020

Carl Edwards Backflip 

To stand on the top of one's car, cheer needlessly, and then backflip off the top of your car. A celebratory act.

He did a Carl Edwards Backflip after getting a date to the prom.

Carl Edwards Backflip by WrestlerGuy May 11, 2013

Backfire 

to bring a result opposite to that which was planned or expected.

They never learn even after all the games they play continue to backfire on them.

Backfire by Goddess12* December 22, 2013

Backflip guy 

The term of acknowledgement given to Ethan Nestor (crankgameplays) due to the backflip he did at the 'markiplier and friends' panel to show his affection to Mark Fischbach

Oh look! It's the backflip guy hanging out with markiplier!

Backflip guy by Simpinson69 December 9, 2020