Riding a skateboard while under the influence of marijuana where the experience can be compared to riding a hoverboard from Back to the Future 2.
"Man, I blazed before taking the board out. I was Marty McFlying all afternoon!"
by D2U3R4 May 08, 2009
To walk backwards haphazardly, usually resulting in an unwanted encounter or physical altercation. Derives from Marty McFly from "Back to the future", as this action usually precedes a very bad event.
That kid over there was Marty McFlying all over the store and knocked down the tower of sodas.
by F. Millmore April 22, 2010