Here are a few options for the text, depending on where you intend to use it (e.g., a game store description, a social media post, or a story intro).
If a creature within 5 feet makes an unarmed or grab-based attack against you, you can use your Reaction to flick the blazer’s lapel into their limb. The attacker takes 1d4 slashing damage, and you gain +2 AC against that specific attack. Critical flavor: On a natural 20, the lapel slices a button, badge, or tie clean off the attacker. metal edge girl blazer rpg