covering your back. six comes from being behind a person (six o'clock position). so "watch my six" is "cover me from behind"
SWAT Team Leader: Watch my six boys, this is goina get ugly
SWAT Team Members: Roger that sir.
by Wite Kastle October 6, 2006
Military slang for "watch my back".
"Six" comes from six o'clock position.
Operator 1: "Dude, watch my sixin there."
Operator 2: "Of course, man!"
by XxVinrAlfakynxX July 2, 2017