If Crowley's hands are free, he can use them to take his jacket off. That's a good plan. He hisses a little as Aziraphale finds a sensitive spot down the side of his ribs, something not-quite-ticklish, and distraction from that means he bites at Aziraphale's neck instead of kissing. Whoops. But then biting seems a good plan too, so a few more of those, just small little nibbles...the angel has to understand that need, given how much he likes tasting things...

And once his jacket's off his hands are free again, to do things like undo fiddly waistcoat buttons, but at that point Crowley stops. He might actually be blushing. "This--" He nods his head towards the waistcoat. "...can I?"

...yes, it's ridiculous, but he's been wanting that waistcoat our of the way for centuries, bless it. Aziraphale not in the waistcoat has become the equivalent of other people looking at their partners in lingerie.