Is it them getting carrying away, this? Or the this whole scene, perhaps, with the costumes, the whine, the locked door, the music. The evening of dancing and talking and holding each other's arm in a silly little party, ignoring their overall situation for once?

Maybe it is. And Aziraphale sure feels that fluttery feeling so much stronger, feels his heart race, all those feelings they have no justifiable reason to have, and yet...

His look softens even more as Crowley's hand moves to the back of his neck. He glances at their lips as they move closer. And, finally, he closes his eyes, leaning up to meet them in a kiss.