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."
by BBEmpress March 18, 2016
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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."
by BBEmpress March 21, 2016
Get the GY6 mug.