After a really serious depressing prediction about the future of an old pensioners death the definition is when the old pensioner makes a funny remark which ruins the seriousness and brings the convocation back to normal levels.
Psychic: you will burn in the fiery pits of hell for the rest of eternity....
Pensioner: I'm not boiling in no freaking coldron
Psychic: well that was a backfire
When you're about to fart, and something extra (and usually liquid) explodes out of the ass.
I was going to light my fart on fire at the party, but a few seconds later everyone got hit by my backfire.
When a guy cums so hard, he ejaculates into his own face.
Dudes, I hella thought she was going to swallow, but she totes made me backfire.
When a man is receiving a blowjob and upon finishing inside the mouth of the giver, the contents are spat back in his direction.
Last night my girlfriend backfired all over my chest!
When a guy receives a blowjob and cums so hard it hits him in his face.
Dude, I was getting this wicked BJ and I thought she was going to swallow, but she made me backfire.
when a guy cums hard enough to blow his load into his own face.
I thought she was going to finish the job, but she pulled off early, and I backfired.
That fucked up half-choke/snicker sound you let out when you took too big of a hit, but then hang onto it...
Back Fire is the action like in Up in Smoke, when Cheech hits the Maui Wowie Labrador joint, and Chong tells him "Toke it up! Toke it up man!"