From the movie "Black Hawk Down",The character Hoot (played by Eric Bana) is on base at the cafeteria when the Ranger commanding officer Captain Steele points out to Hoot that, whether an undisciplined Delta Operator or not, his M4 carbine should be safeties-on in the barracks. Hoot replies, "This is my safety", and bends his index finger. Used commonly by airsofters, paintballers and military enthusiasts alike.
Dude, don't point that thing at me.
Don't worry, I got my Eric Bana safety on.