GY6

GY6 means "got your 6" as in "got your 6 o'clock" like "got your back"

Friend says to another friend: "GY6, Buddy."

Friends responds: "Got your back too."

GY6

GY6 is short form for "got your six" like "got your six o'clock". It is another way to say "got your back".

Friend: "GY6, Buddy."

Reply: "I got your back too."