(Noun-Verb) - To run directly into your offensive lineman's rear end so violently that it in turn causes the quarterback to misplace the pigskin out of his hands and onto the ground ultimately causing a fumble.
Mark Sanchez is the pioneer of the Buttfumble.
To completely fuck-up in your profession. A butt fumble (n) or to butt fumble (v).
Example 1: Did you see Mark Sanchez, the Jets quarterback, run into the ass of his own lineman and lose the football? That butt fumble has been voted the worst of the worst sports mistakes for two months straight now.
Surgeon A: “I can’t believe I amputated the wrong leg of that patient."
Surgeon B: “Man, you totally butt fumbled that operation. You're probably going to get your license suspended."