I saw this fanart by @strudelcreep and had the ridiculous idea of Crowley and Aziraphale just being Adam’s shoulder guides (so to speak). Like…
Instead of Heaven and Hell sending angels demons to earth, they get assigned a human to guide and develop (kinda like fairy god parents! but not really).
And they’re not a constant presence, just around when a particularly moral situation calls for them. Sometimes the human’s decision will turn out good or bad, depending on who gets to their post first.
Crowley and Aziraphale meet on Adam Young’s shoulders when he is old enough to make decisions for himself, and that’s the only time they see each other. Crowley laughed when Aziraphale let Adam rifle through his mother’s purse for money, thinking he was a dumb angel to let the kid get away with something he would convince the boy to do… until his mother caught him and gave him a stern talking to, ensuring Adam would never do it again without permission.
“Now he’s learned a valuable lesson,” Aziraphale would explain with his hands clasped in front of him, head high and giving a bit of an involuntary wiggle.
Crowley just stared, one leg out, treading on the edge of Adam’s shoulder to get a full view of the angel. Aziraphale had taken a peek over at him and deftly looked away, patting down his robes and vanishing after being unable to take the demon looking at him any longer.
That’s how Aziraphale worked, he led Adam into good or teachable moments, and Crowley found that so admirable (especially considering he had developed quite a liking to his assigned human, he and Adam would stay up late, discussing the dark and depressing times of the world and how to chase the chickens in the backyard to see how high their useless feathers got them in the air). Crowley only heard of shoulder angels commanding good deeds and forcing “right” answers to lingering thoughts their respective child had, rather than letting them choose for themselves or at most, giving a gentle nudge.
“You know, you’re not very commanding.” Crowley tried speaking to the angel, Aziraphale, again. He liked hearing him talk, however brief their exchanges were, and always had an itch to keep their conversations going, get just a little bit more out of Aziraphale, before he up and vanished.
Aziraphale snuck a sideways glance over at Crowley, brows knit together.
And Crowley explained to him how he heard from Beelzebub that his partner Gabriel was the worst know-it-all, or from Hastur that Uriel barely even spoke to their child, only waving their hand with a bored look and vanishing without ever speaking to the smelly demon across the way.
“Yes, well…” Aziraphale tugged at his waste coat, he had recently started copying human dress code, as Crowley had, who enjoyed how it all tailored accurately over his human form and showed little to the imagination. Though the angel preferred jackets and waistcoats and slacks that hid his figure a bit more casually.
“No one ever learns from force. Otherwise they turn into… oh, whats the monsters that humans came up with… with the goopy faces and green skin?”
Crowley raised his eyebrows so high they nearly touched his hairline.
“Er, zombies?” He guessed.
“Ah! Quite right. They’re turn into zombies. Or, you know, something of that nature. Following orders blindly without a care of the bigger picture.”
“Mm…” Crowley hummed, hands slipping in his jeans pockets. Gazing over at Aziraphale with unique fondness until the angel started to squirm, though Crowley doubted it was from awkwardness or feeling uncomfortable. He’d certainly tell Crowley otherwise, as he had so boldly in the past.
As Adam grew from a child to a teen, the angel and demon found their time together… enjoyable. They lingered on Adams shoulders, careful not to let the young boy know of their constant conversations, or worse yet, needing their help and finding one or the other on the wrong shoulder.
Aziraphale liked Crowley, which took a long time to admit to himself. He liked how sweet and nice the demon was (although after that admission, Crowley had Aziraphale nearly nose-to-nose, fists in his lapels, insisting with a hiss that he was not nice). He liked how his golden, serpentine eyes shifted and changed depending on Adam’s mood. He liked how Crowley never really forced the boy down a path of evil or unrighteousness… just little schemes and tomfoolery that never hurt anyone.
So honestly, really, it wasn’t too much of a shock when this feeling of respect and admiration turned into something more… and to Aziraphale’s delight, Crowley felt the same.