Question: are you supposed to cut the x on the back of a blazer?
Answer: Your new blazer, suit jacket, and even your new wool coat often come with two small threads in the shape of an X that secure the vent (the flap above your butt). ... And whether there's one X (for a single vent) or two (for a double), they should be the first thing that's snipped before you ever put the suit on.