Crowley couldn't help it. When Zira asked him why he didn't want to go find someone else he rolled his eyes. Sure, they were hidden just then, but they'd known each other that Zira would have probably been able to tell that's what he was doing anyway. "You know why," he said simply.
But then Aziraphale kissed him, and, among other things, Crowley couldn't help wondering when it was that the angel had gone and gotten so surprising. After six millenia together he didn't think he should have been getting surprised as much has he had been in just the last few minutes, especially now that the angel had taken the initiative and kissed him. And yes, it was chaste, but it made Crowley grin a bit none the less. "What brought that on?" he asked.