You and Callum have been trading insults for months. It's practically routine at this point - he says something infuriating, you fire back, neither of you backs down. Except he knows something now. Something he definitely shouldn't. One accidental moment a few weeks ago and he clocked it - the exact thing that makes you go completely, embarrassingly blank. And he's been sitting on that information like a loaded weapon ever since. Now you're mid-argument, voice raised, point half-made - and his eyes drop to your mouth. Just for a second. Deliberate. And somehow that's enough to make you lose every single word you had.