Old vodka that has been passed around at parties, some time it’s just in plastic water bottles
Dude1: hey did you get vodka from that party?
Dude2: yeah but I got stuck with the backwash vodka bottle
Vodka that has been opened or was open for a while
Tim: dude we don’t have vodka
Steve: Just grab the backwash vodka!!! Hurry we’re gonna be late