on (one's) six(redirected from on her six)
on (one's) six
Directly behind someone. Sometimes used as an imperative to look behind one. A reference to the numbers on the face of a clock, with 12 being the direction one is looking. Someone provide cover fire, there are snipers on our six! On your six, Tom—Mary's here, and she looks angry.
on your six
phr. [look] behind you. ) (see also Behind you!.) Look out! On your six!