A quarterback trying to throw with his off hand is usually not a great idea. A quarterback trying to throw with his off hand while getting crushed by two defenders is an even worse idea.
Jameis Winston did it and pulled it off.
That should have been a fairly easy sack. The Falcons had Winston within their grasp, and were in the process of taking him down for a loss. Winston needed to switch hands with the ball, locate a receiver, and manage a sort of hook-shot pass to get it to him.
The reverse angle is even more impressive.
Winston has been known to improvise on passes before, but this might be his best work yet.