Do a barrel roll!

[Sarah]

Comes from Starfox 64. A character would command fox to do a barrel roll in order to prevent being shot to deadness.
A barrel roll is when a fighter pilot makes his ship turn over, very quickly, in mid-air. It makes the wings harder to hit.
Its more common practice to shout this phrase at friends while they play video games. Especially if they cant do anything roll-like. The purpose is to be obnoxious, and quote old video games. Two of most peoples favorite things.