Crowley leans in to the hand on his hair like a cat being stroked. He might even purr if he weren't distracted.

But he has a task, and is attending to it diligently. He kisses Aziraphale's neck again, then sucks on the same spot as he carefully adds another digit. Not as deep, the same slow thrusting as before, and then as the angel opens up he scissors his fingers to stretch them further. By this point he's left what will be a very pretty bruise on his lover's neck, and kisses the spot again lightly.