Comes from when the player readys his knife and slashes the knife on a wall of in the air.
Also used as a word for shank.
The Term VO has been around for less then a year come to date.
VO: EMBRACE ME !!!
Girl: VO, your hugs are the best !
VO: I know(:
Girl : typical VO ! ahah
"Nope. It was a VO."
"I got VO'ed into seeing "The Backup Plan" by my girlfriend last week. I'm such a pushover.
Person 2: Well vo.