“I got your 6”, or similar sayings, means I got your back. The term comes from the 6 o’clock positioning of a clock, with the 12 position at the front and the 6 at the back.
In the video below, a husband and wife are talking as the wife is backing the car out of the driveway. Then, a man with a gun approaches them from behind.
The wife is the first to notice the man, and she alerts her husband of the closing-in threat. She’s got his 6.
Earlier in the video, as the husband comes into frame, we can see a firearm on his side. We’re not sure if the bad guy saw this firearm, but it led to a brief standoff between the two.
Now that the fight is on, the husband has got his wife’s 6. That’s teamwork.
Luckily, the bad guy didn’t try anything stupid, so the good guy could prevail. He places some shots on target, and it doesn’t look like either the husband or wife were injured.