When something unexpected, strange, and indescribable happens to you.
My friend's vacation got canceled at the last minute by Blackout 2003. Then he had to walk 80 blocks home and up 25 flights of stairs with a bum leg and a huge suitcase. Man did he get Leafed.
Of or pertaining to the cannabis plant, getting "blazed", "stoned", smoking some "tree" (hence the leaf origin).
The act of becoming leafed, or leafing, is becoming stoned, or blazing.
"dude, we getting leafed tonight?"
"Bro im still so shot from last nights leaf sesh. can we just get shmaaawww instead?
"no dude im leafing tonight i need to release some stress"
"iight well im not a stone-head so im not leafing, peace leafer"