The horrid event that occurs when your woman craps in your bed after you pull out of her ass. The boulder toss part happens when you forcefully hurl the backfire at the rear of her cranium. Very nasty...
"Yeah man when I pulled out and she backfired on my new linens, I picked her fecal matter up and nailed her with it!"

"Wow man, the legendary backfire-boulder toss!"
by Hanzo Steel May 12, 2006
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