It’s a reaction Sakusa can’t seem to control, Atsumu’s learned, like the shirking of his gaze and the tightening of his grip on whatever he’s holding. His words are always clipped and disinterested in response to whatever suggestive thing Atsumu’s saying, but his body language betrays him often enough to give Atsumu the incentive to push a little further.
“Sure? I can arrange ‘em into a neat little list. Ya like those, right? Organisation gets your dead heart pumpin’ real fast. I can hear it.”