Nitrous oxide. Can be bought over the internet for 'culinary purposes'. A cheap drug that makes everything funnier, usually taken in a balloon so you get oxygen as well and don't die.
Mike: Dude do you wanna buy me some laughing gas?
Brett: Shit man i'm skint you get it.
by Abraham Smith April 30, 2007
Nitrous oxid,e a gas used as a propellant, in engines, and as a drug
He had apparently had access to laughing gas and fell down after inhaling it.
by The Return of Light Joker April 21, 2010
(Someone tells an awesome joke)
(Someone laughs & farts as a result)
"Dude, what the heck was that?"
"Aw, sorry man, it was laughing gas."
by Flamin Jeez April 24, 2009
Laughing so hard or so suddenly that one farts
Evan: Jules has laughing gas.

Chris: Like, to get high?

Evan: No, like, farting.

Chris: Lol!! (*farts*) Excuse me.
by NotDainty March 1, 2015