You are going to watch out and be a second set of eyes for someone. You will look out for their best interests and let them know if they have missed something. You will stick up for them.
Dbyrn: Hey, Frappe, I saw some kids messing around near your car, looked like they might be think about breaking in.
Frappe: Dude, seriously?
Dbryn: Yeah, I took some pix of them with my cell phone and they saw me and split really quick.
Frappe: Thanks Dude!
Dbryn: Don't worry, you know I've got your back.