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

Bachle 

Glaswegian An unkept individual. Bachles usually wear clothes that are crumpled and ill-fitting.

Och, look at that shackly wee bachle!

Bachle by c.linguist August 12, 2020

Build Back Batter

The act of withdrawing the penis during doggy-style sex at orgasm, and pointing the head of the cock above the buttocks and building a puddle of ejaculate (baby batter) on the small of the partner’s back.

After a few minutes of my stimulus package from behind, Alexandria hysterically lobbied me to pull out and Build Back Batter (BBB) on her tramp stamp.

Build Back Batter by Panama Pucker December 22, 2021

Dropped My Back 

To heavily defecate yourself

Bollocks, i've just Dropped My Back

Dropped My Back by Greg_the_Smeg February 15, 2019

Armenian Back Nair 

When one is asked, forced, tricked, blackmailed, threatened, or willingly helps to apply Nair to an Armenians back. This is no small task, and will take serious forearm strength to wipe the rainforests of chemical burning hair away.

1. Hey big dog, you coming to jam tonight? No sorry champion, I got baited into another Armenian Back Nair night followed by a Cunnilingus Hedonist session and no reciprocation.

Armenian Back Nair by GIRTHQUAKE72 November 10, 2019

hang back 

to delay further prospects as by lingering in anticipation of developing events or circumstances; to stay behind; to show reluctance

After class was dismissed, I decided to hang back and try to grab a moment of the teacher's time.

hang back by Scott Fairbairn September 8, 2008

Don't Look Back In Anger 

A song by Oasis, what else?

But Don't Look Back In Anger, I heard you say.

Don't Look Back In Anger by Carbona Ramone April 20, 2021