All you have to do is
-Disable your internet (Go to network settings and disable it)
-Go to a local game
-Hit the box until you get it (Note: It is very rare to get, so don't give up)
I just got it so if you have PS3 you can too.
Also, I don't know if you have to have map packs/season pass to get it. I do but not sure if you can till get it without the season pass.