Aziraphale would appreciate the sentiment but dislike the execution, because it'd necessitate him to wear an 'I'm Aziraphale' t-shirt to match. Perhaps he could get away with a button pinned to his lapel instead.

(And, of course, they would need shirts with reverse wording, because there are times when Aziraphale is not the more responsible one by any means.)

There is a peal of giggles at the nose nuzzling, but the angel settles down soon enough. "That's a risk I'm willing to take," he replies, gently stroking Crowley's back. "Although having you fall asleep in my arms is another one of my fantasies, so it's a win-win for me."