The handle bar that is on either side above a seat in a car, that is used when the driver makes too sharp of a sharp movement with the car, such as a sharp turn, and the passenger or passengers usually say, "Oh Shit!" and grabs onto that bar. Hence "O.S.".
Driver: "Grab onto your O.S. Bar!"
Passenger: "What?"
Driver makes a sharp turn
Passenger: "OH SHIT!"
Driver: "Told ya."
Passenger: "What?"
Driver makes a sharp turn
Passenger: "OH SHIT!"
Driver: "Told ya."
by makoli May 17, 2009