Seen many interpretations of this situation, this ones mine

Crowley had been lying on his couch for a while now. Four years to be exact. He had been lying here since he returned to his flat after the whole London blitz church bombing thing. The reasoning being that it was the most comfortable position to be in, laying with his feet hanging off the edge not being touched by anything. He'd been steadily keeping himself drunk, even though it wasn't the best option for a demon to be. But that helped with the pain he was currently stuck with. He had been lying there barely lucid when he heard a rapping on the door.

"Oh for Satan's sake, who the hell is it?" He muttered, then raising his voice. "Whoever the hell you are, if you know what's good for you, you'd go the hell away, before I make you regret coming to my door."

"Crowley? My dear, are you in there?" A familiar voice called thru the thick door.

Crowley lifted his head to stare at the door blearily. "Aziraphale? Z'at you?"

Crowley waved his hand and the door unlocked, swinging open to let the angel in. "Crowley? Where are you?"

"Here." Crowley gesturing from his vantage point on the couch. "What are you doing here, angel?"

"Well, I haven't seen you around for quite some time, and I was wondering if you had even heard that the war was over."

"Oh really." Crowley propped his head up. "So who won?"

"Germany surrendered just a few days ago. All of London has been celebrating since." Aziraphale smiled broadly, glad that evil had been vanquished.

Crowley layed back down. "Good. I hate having to switch language. Very annoying."

"I was wondering, Crowley. If you would like to nip off for a bit of celebratory dinner?" Aziraphale still stood close to the door, looking around at the big emptiness of the demon's flat.

"Nope, I'm perfectly happy lying here."

Aziraphale walked around the couch to look at his friend lying on the couch. They had lost touch so long ago due to a falling out, and Aziraphale had been surprised to see the demon again four years ago.

"Really, Crowley? Are you that put off that evil lost?" he furrowed his brows staring down at the demon's face. the demon glowered back up at him.

"No, I'm not put off that evil lost. Come off it, angel. Those bastard's made things difficult for the both of us. I'll have you know that this is just the most comfortable position in the whole flat, and there should be nothing wrong, in either of our side's eyes, with lying on my couch with my feet hanging off the edge." Crowley's mood was not getting any better.

Aziraphale looked down at Crowley's feet and that's when he realized he wasn't wearing shoes, and the reasoning was due to the bad injury on them.

"My dear! Your feet! What on earth happen..." Aziraphale's voice trailed off when it dawned on him.

"S'the kind of injury that happens to a demon who decides to walk into a church." Crowley mumbled, mood shifting/

"This is my fault!" Aziraphale cried out in despair. "If I hadn't gotten myself into that situation-"

"Don't go starting to blame yourself angel. It was my choice to go into that church. I knew the risks and danger. There's no one to blame but myself." Crowley rolled over to his back, glowering at him, face a mix of anger and pain.

Aziraphale swallowed down his apology. "They haven't healed yet though?"

"No. Apparently holy wounds don't heal as fast. Can't miracle it away. It would be easier if I could just get into a shed cycle."

"Shed cycle?" Aziraphale momentarily forgot his upset.

"Yeah, I've a snake form remember? If I could shift into that I could just shed away the injury. S'what I did in the past."

"Oh! Well, that makes sense." Aziraphale nodded.

"Only problem is that they hurt so damned much I can't concentrate long enough to fully change." It was the first thing he tried as soon as he got home that night, but to no avail.

"Oh...oh dear. Perhaps if I..."

"Don't even think about trying to use a miracle on me, angel." Crowley cut him off. "Wouldn't want you to get in trouble for healing a demon." The last bit was muttered under his breath.

Aziraphale stood there at a loss, still feeling guilty for the injury that Crowley got on his behalf. Then he got an idea. He walked over to the edge of the couch where the demon's feet dangled. Said demon watched him steadily wondering if the angel had the capacity to defy him. Wouldn't be the first time.

"Perhaps if I..." Aziraphale lightly tapped each of his feet and suddenly Crowley found he could breathe; not that he really needed to. But the searing holy pain was suddenly gone. Crowley sat up with a start, looking at his feet, seeing they were still scarred. Only now they felt like a normal injury.

"What did you do?" He pondered.

"I removed the blessing from the injury. Now you should be able to help with the rest." Aziraphale beamed at him, and Crowley nearly forgot to breathe again.

"Well I hope you don't expect a thank you, angel." The demon groused with a sigh. "At least now I can get hell off my back and do those assignments. Any longer and the prince would start to notice."

"Oh, your behind? Perhaps I could..." Aziraphale wrung his hands.

"What are you inferring, angel?" Crowley said, quirking his eyebrow at the heavenly being in his apartment.

"The arrangement." Aziraphale whispered. "I DO still owe you for... back there. It's the least I could do, until your back on your feet that is... oh dear! I mean, or rather I didn't..."

Crowley felt suddenly much better at the sight of the angel getting flustered. It was something he wont admit he had been missing for the past sixty years. "Of course you 'didn't mean' anything, angel. I understood your intent either way. If you want to do that you can, I won't stop you. But just this one time, eh?"

"Right! Right." The angel nodded. "So where...?"

Crowley gestured to the corner of his room to the fax machine on a desk. After the messengers set fire to one of his plants he got it set up to receive his assignments that way. It was much more convenient. He lay back down on the couch, eyes still following his friend.

"Ok, so... I guess I'll go and do these. Do rest up, my dear. Perhaps later we can get something to eat?" Crowley gave a shrug. "Right. Rest well!"

Crowley didn't take his eyes off the receding sight of the angel. He felt the sudden urge to clear the alcohol from his system and follow Aziraphale. He shook his head and stared up at the ceiling, thinking more to himself as she most likely wasn't even listening. 'What are you getting at here?'