Good old fashioned loverboy
Everybody knew Crowley was tempting and so did Aziraphale, it was just that he never dared to do literally anything because of course it was considered a sin in heaven.
The Angel had always liked Crowley but hadn't realized he loved him until Crowley had gone through the pain of walking on sacred grounds just to save him from being discorperated and more importantly his books. But loving him was never something Aziraphale was proud of and rather something he would push away for later or... Never.
However he found his previous standards entirely vanishing through the whole apocalypse problem. He had again seen Crowley take the risk of being discorperated to save him and the fact that the demon would have left the world to die and instead go drinking until numb without him had the platinum blonde angel realizing his love for that particular demon again.
There was also the fact that, after the apocalypse that didn't, they seemed to have left and also scared their sides. Aziraphale had to admit the whole switching body's story was kind of funny.
So that left them without rules really and since the almighty didn't seem to care, the Angel hadn't fallen after all, there seemed to be no obstacles left for him to finally be proud of his love and admit it to Crowley. But Stil the chubby angel was scared...
Scared of judgment from the demon, scared of rejection and mostly scared of ruining their centuries lasting friendship. And so it was again Crowley initiating things as Aziraphales phone was ringing a Saturday afternoon after the apocalypse that wasn't:
"Yes A. Z. Fell's Bookshop, how can I help you?"
"Aziraphale?"
"Crowley my dear what's the matter?"
"I'm actually really bored angel... Would you care for a dinner at the Ritz with me?"
"Oh that sounds delightful Crowley I suppose I meet you here?"
"Yes I'll meet you at nine precisely"
"Sounds great, see you then"
Aziraphale hung up with a smile lingering on his lips the rest of the afternoon as he made tea, sorted through his books and had to deal with a few costumers.
It was nearly nine in the afternoon and Aziraphale was straightening his clothes and cleaning his cup of tea from earlier as he heard the familiar voice of the red haired demon from the front door.
"I'm coming", he shouted back before running up to the front and smiling at Crowley, "ready". The demon smiled slightly then holding the door open for the blonde.
Aziraphale closed the shop and was led to the Bentley by Crowley, who then jumped into the driver's seat starting the vehicle.
The slender demon was driving oddly slow and concentrated to the angels surprise and so he looked at him in confusion asking:"Crowley dear what has gotten into you? you are watching the road and haven't hit anyone the entire way", with a slight giggle.
The demon found this adorable and answered:"you said I go to fast for you..."
Aziraphale blushed at that, looking down at his lap for the rest of the drive, which didn't last much longer.
Soon they arrived and the redhead opened the door for the angel."Thanks dear", he got out of the car and found himself seated at a table across from Crowley soon after.
He ordered himself some Crêpes and wine for the two of them. Crowley didn't eat as always, not that he has to, Aziraphale was just one to really enjoy food.