black gas 

The worst smelling flatulance the hangs heavy in the air.

I don't know what I ate, but I have the black gas.

black gas by Xanaxmind June 1, 2017

Double gas back 

When you burp and fart at the same time

Oh shit i just had a double gas back

Double gas back by Diarrheabruh April 1, 2022

Gas her back end 

To fuck one's back end

Bro 1: Bro I wanna hit up this thottie but I don't know what to say
Bro 2: Bro just tell her you're gonna drug her and gas her back end.

Gas her back end by The gasser June 10, 2018

Gas Station Back Up 

A dirty hammer usually used for beating things live a retard. Can be used as an insult if desired.

Let's use the Gas Station Back Up.

Gas Station Back Up by JustaStoner January 14, 2020

Gas her back end 

To fuck one's back end.

Bro 1: Bro I wanna talk to this girl but I'm not sure what to say to her.
Bro 2: Bro just tell her you wanna gas her back end.

Gas her back end by The gasser June 11, 2018

Back Gash 

- Generally a term used to describe one's anus (a.k.a arse hole)

- Comes from the word gash - which is a slang word for a vagina

- Back Gash is a term is often used by gay men.

Gay 1: How was last nighe?
Gay 2: Good, but my back gash is really sore! He was HUGE!

'I shouldn't have had that indian food last night, my back gash is killing me]'

Back Gash by Liam D - Official Welsh Scene Personality April 20, 2008

back-door-gasm 

A back-door-gasm is the cumgasm a guy has when he seeds another dude in his asshole.

Matt has at least two back-door-gasms in me tous les jours!

back-door-gasm by eda-skip November 1, 2021