After the oysters,  which had been quite scrumptious, Crowley stuck around for another cup of honeyed wine. And then another. And before long they had finished an entire amphora and Aziraphale knew neither the time, nor how it had passed so quickly. He was, however, well-sated, and, if he were to be entirely honest, not displeased with the company.
The tavern had yet to close, which might have been a testament to Rome’s extraordinary hospitality, or—and he couldn’t be sure—a tipple of demonic intervention. His own celestial influence certainly wasn’t at work, but he could see the appeal of just one more cup down the hatch. And perhaps another round of oysters.
As soon as the thought passed from his mind the oysters appeared, dropped off by a now exhausted looking server. Aziraphale’s mouth bunched up and he turned what he hoped was a properly scolding glare in Crowley’s direction.
Crowley, who had begun to lounge with more and more lanquidity over the course of their evening, shrugged. “Don’t pout, angel,” he said. “It’s my job to know what people want but don’t intend to ask for.”
“I’m not people,” Aziraphale protested.
Crowley shrugged again and slurped back an oyster. Aziraphale watched longingly as he swallowed. He didn’t have anywhere to be just yet.
“It’s posssssible these are better than the last ones,” Crowley added with a sly glance.
Aziraphale tsked. “Oh, you,” he said. “Fine. If I must.”
“You don’t have to do anything you don’t want to do.”
“Quite right,” Aziraphale said, before tipping back an oyster of his own. They were divine, he couldn’t argue. “Although,” he amended, once the sweet flesh and herb had cleared his gullet. “That’s not really true for either of us. We answer to a higher—“
“Power. Right. What brings you to Rome anyway? You mentioned a—a tempting?” Their initial encounter seemed days ago even though they’d only sat and drank copious amounts of wine together since.
“Mostly run of the mill,” Crowley replied. “Mucking about with some disenchanted senators. You know the sort.”
“I’m sure I do,” said Aziraphale, thinking of his own celestial instructions.
“You? Or did you just come for the snacks?”
“I’m not sure it’s wise to tell you.”
“Oh, come on.” Crowley rolled his eyes behind his stupid little glasses. “I’ll recognize a miracle when I see one anyway.”
“But what if you try to thwart me? Once you—once you know what I’m meant to achieve.”
“But,” Crowley said, pointing at him, and going a bit squinty around the eyes like he did when he was about to make what he clearly thought was a clever point  , “what if our respective missions are aligned and we could, I don’t know, help each other out?”
It sounded lascivious, when he put it that way, and Aziraphale couldn’t place why. It must have been the atmosphere—Rome was positively cosmopolitan in comparison to Jerusalem. “Absolutely not,” he said. “Out of the question.”
“It’s the principle of the thing. It’s not right.” He gulped his wine.
“Suit yourself,” Crowley said, “but—“ and now he leaned in very close, close enough that Aziraphale could smell sweet wine on breath he didn’t need to take. “I have it on good authority that change is coming to Rome, and that our camps are in agreement on its necessity if not the…coursssse of action.”
Crowley hummed directly into his ear, and Aziraphale realized he’d draped an arm over his shoulder to get nearer. “Yes?”
“Caligula has become a bit—a bit of a bother.”
“A bother!” Crowley barked a laugh, leaning away and taking a striking amount of body heat with him.  “Count on your lot to distill flagrante delicto with your bloody horse down to being a bother.”
“Crowley, don’t be rude. Those are just rumors.”
“No, they’re not.” He had the audacity to leer.
Aziraphale took another long sip of wine and discreetly miracled himself another cupful. “Oh,” he said. “Goodness.”
“Indeed. Christ, I hate horses. Can’t imagine why anyone would want to get that close to a blasted horse. Great, unpredictable bastards.”
“Listen,” Aziraphale cut in. “If we’re both here to ensure the end of this, ah, reign—“
“Then I suppose it couldn’t hurt to put our heads together on it. You know what they say!”
“Don’t look a gift horse in the mouth?”
“No, Crowley. Two heads are better than one. And besides, my side isn’t all that troubled by the horse thing, rumor or no. He’s been—“ it was Aziraphale’s turn to lean in and Crowley obligingly met him halfway. “He’s been calling himself God.”
“Ahhhhhh, can’t have that.”
“Imagine that’s a point of contention for my side as well.”
“So.” Crowley reached into his toga and dumped a handful of coins on the table before them. His voice dropped into a conspiratorial whisper that made Aziraphale’s stomach turn to liquid. “What’s your next move?”
“A party, actually.” He sounded sheepish. “Tomorrow at the imperial villa. One of them, at least.”
“Oh angel, really?”
“It’s reconnaissance!” Aziraphale said. “Important information gathering. Must make sure we have the facts straight, otherwise Gabriel will have my head for bringing about a—another unwarranted public stabbing.”
“Caesar,” Crowley intoned.
“That wasn’t your fault.”
“No” Aziraphale said archly. He gave his demonic counterpart a look. “I suspect it wasn’t, but I got a holy verbal lashing for it all the same.”
“What did they even care? It’s not like Her reach is even—“
“Ineffable, I know, angel. Yours is not to reason why—“
“Gentlemen,” said a perturbed sounding voice in Latin. “We’re closing.”
“Well.” Crowley stood and stretched, looking rather more serpentine than usual. “See you at the orgy then. I’ll look for you by the buffet.”
“The buffet—the orgy?” Aziraphale sputtered. “What?” He could feel his face grow hot, which made no sense,
Crowley slid his glasses down just so and winked. “Don’t get your toga in a twist, angel. I’ll protect your virtue.”
“I don’t need protecting,” Aziraphale insisted, frowning. “I’m a heavenly soldier!” But by the time the words had left his mouth Crowley was gone and he was alone, save for the annoyed tavern employees who looked ready to twist his toga for him.
Crowley found him by the buffet, where Aziraphale was lingering and certainly not lurking.
Looking at the abundant spread of pears, figs, ostrich, all manner of other animals stuffed into a roasted boar, sautéed dormice in thyme, more oysters, whole fish with golden skin seared to perfection and drizzled with garum, not to mention a heaping pile of delectable looking nuts and olives all spilling out around the display like a wave of earthly pleasure given form was a far cry better then looking at the actual room.
The only thing the Emperor Caligula liked more than food was sex. Aziraphale couldn’t relate.
“Well, this is a show,” said Crowley, sidling up to him with a sidelong look. “I’d heard rumors too, but.”
“Yes,” Aziraphale hissed. “Didn’t do it justice.”
“It’s like he’s directing a stage play.”
Aziraphale popped a handful of walnuts into his mouth to prevent himself from speaking. He studied a pile of seared sausages bedecked with sage then thought better of it.
“Having fun?” Crowley asked, a little too gleefully.
“Not even a little?” He scooped up a pear and tossed it deftly from hand to hand before offering it to Aziraphale like a invitation to sin. “You love pears,” he said.
Aziraphale licked his lips before he could stop himself. He did love pears. He swallowed, his mouth very dry and chalky.
“Good lord, you’re incorrigible,” Aziraphale said, and grabbed a pear of his own off the abundant banquet table. Crowley watched him take a bite, about as focused on Aziraphale as Aziraphale had been on the comestibles.
“Sweet?” He asked. It sounded like a trick question.
A bit of juice dribbled down Aziraphale’s chin. Behind him, several voices created a chorus of moans. He wondered if the pear Crowley had offered would have been sweeter still. And perhaps just for him. “Yes,” he said, reluctant.
“Stop. What?” Crowley had edged closer, was nearly crowding him up against the table. Aziraphale put one hand on the marble edge of it to steady himself. Crowley took the pear from his hand, where Aziraphale had clutched it to his breast, and took a large, indecent bite.
“You know what,” Aziraphale said, watching him chew. Watching him swallow. Watching his lips, thin as they were, glisten momentarily with juice before his unconscionable tongue licked them clean. Aziraphale reminded himself to breath. “Just because we are at an orgy does not mean—“
Crowley smirked at him. “When in Rome,” he said.
“But we are in Rome.”
“No, it’s like, when in Rome do as the Romans do.”
“That doesn’t make any sense!”
Crowley scowled at him. “Trust me. It’ll catch on. I need wine.”
“I—“ Aziraphale watched him stride away into the crowd of writhing bodies, barely paying them mind. “Caught on the back foot again,” he muttered.
It simply wouldn’t do. He shouldn’t have agreed to this at all, let alone allowed himself to end up on the tempted side of an obvious temptation. He was better than that, and it was Crowley, for goodness’ sake. Crowley, for whom it was likely all a bit of sport. Why not rile up the angel. What good fun that would be. A little light tempting before doing the real work.
Aziraphale huffed. He didn’t like being practiced on, and it wasn’t Crowley’s usual style either. He teased, he prodded, but he didn’t tempt, and he certainly didn’t tempt Aziraphale to lust. Gluttony, maybe, but Aziraphale was self-aware enough to see through all of that. He was no glutton, he was simply an angel who enjoyed the finer things and there was no harm in that. After all, it was a celebration of Her divine work to take part in Earth’s pleasures. He was sure of it.
And now Crowley had gone and left him alone at what was turning out to be a much more explicit sort of party than he’d imagined. How unexpectedly horrid.
Aziraphale’s face lit up of its own accord. “You’re back!”
Crowley shoved a metal cup into his hand. “Drink up.”
“Is there a balcony?” Aziraphale wondered aloud. He was very warm all of a sudden. Togas weren’t nearly as breathable as they ought to be .
“Yessss,” said Crowley, half-drawl, half sibilant. “It’s through there. I passed it on my way in.” He pointed towards a marble arch festooned with drapes and flanked on either side by murals depicting scenes very similar to the one going on around them. “And, as luck would have it, there’s not a soul occupying it right now.”
Aziraphale raised an eyebrow.
Crowley’s mouth twisted in a funny little way that seemed to say, “who, me?”
“Splendid,” said Aziraphale, feeling inordinate relief at Crowley’s reappearance regardless of his uncouth behavior. “I need some air.”
“May I join you?”
“Could I stop you?”
“Naaah.” Crowley grinned, all teeth.
Aziraphale’s stomach did the liquid thing again, although this time he had a cup of deep red wine with…notes of cherry and perhaps tobacco to counter it.
“And besides,” Crowley added, “I have intel that may interest you.”
“Then lead the way.”
“After you.” Crowley’s free hand landed on his lower back, hot and very distracting even through his toga.“I insist.”
He let Crowley steer him through the the crowd, past partners paired in all manner of configurations, including what looked like a threesome involving one man stretched between two.
“That’s called an Eiffel Tower,” Crowley muttered. 
“Don’t worry about it.”
Aziraphale frowned, pausing to stare a moment. He tilted his head. Humans were very creative.
“Let’s go, angel,” Crowley said, pressing down just a bit more on his back, ushering him onward and then, blessedly, into the night air.
“Ahhhhhhhh.” Aziraphale exhaled once they were outside. He gripped the balcony with one hand and downed the rest of his wine in a long, slow pull. “Sorry, my dear.” He gestured with his cup toward Crowley, who was leaning against railing watching him, arms crossed over his black clad chest, silver laurel leaves glinting in his auburn hair. “I’m a bit—“
Crowley’s mouth quirked up. “Go on.”
Aziraphale shook his head and glanced down at his wine. He heard Crowley snap and it was full again. He took a fortifying sip. “So, what do you know?”
“There’s going to be a murder.” 
“Don’t sound so thrilled.”
“Can’t help it. I had a busy day, and it was fruitful.”
“Well,” Aziraphale conceded, “at least my side won’t have to orchestrate it.”
“Consider it a favor.” Crowley smiled.
“How will they do it? I hope it won’t be terribly messy.”
It was just then that Aziraphale heard the tell-tale smack of battle tested sandals coming toward them. One of Caligula’s praetorian guards, most likely. He could see exactly how this would play out. At best, they’d be discovered, revealed to be interlopers, then kicked out. At worst, they’d wind up discorporated.
Then there would be paperwork .
“You there!” Called a gruff voice that could only be an Imperial guard. No one else could sound that menacing.
“Kiss me,” Aziraphale said, quite frantic and thinking solely of subterfuge.
“Mmmrph,” said Crowley, who didn’t get a chance to say anything before Aziraphale dragged him close and put their mouths together.
The sandals paused, snickered, then moved away.
They didn’t stop kissing. They should, Aziraphale knew, stop kissing.
Someone’s cup fell to the ground. Crowley moaned and his arms wrapped around Aziraphale, his hands coming to rest at the back of his neck and in his curls respectively. He moaned again. His tongue did something that was pure sin and Aziraphale returned the favor, licking at Crowley’s mouth like he could sip the very wine out of his stained lips and tongue.
Now who’s on the blessed back foot, Aziraphale thought, a smidge too smugly for an angel. But oh—oh, then something shifted, and Crowley was moving against him, and the thick, elaborate marble railing was at his back, and Aziraphale quickly realized that he was heading down the path to serious public indecency. He was going to be thoroughly debauched; he could feel it.
He had barely been debauched in private; let alone in public, let alone by Crowley. A demon! His enemy. His—
Crowley fumbled past the folds of his toga and groped at him. Purred directly into his ear, “Oh, angel, making an effort, are we?”
“It seemed—“ he gasped. “Only appro—ah, Crowley—appropriate, given the affair. Are you—“
“Always,” Crowley said. He licked a line up Aziraphale’s throat, leaving a hot trail in his wake. It felt like molten honey. “Part of the job description, love.”
“We should stop,” Aziraphale panted. He pawed at Crowley’s back, at the curtains of fabric around his shoulders. “We should go back in.”
Crowley pulled back to give him a delightedly evil look. “Back in? You wish to take this inside? Join the revelers? Give them a bit of a—“
“No,” Aziraphale whimpered, at the very idea and also because Crowley’s hand had closed around him and was stroking him, fanning a fire he didn’t know he possessed with each delectable pull.
“Tell me to stop and I will,” Crowley said. He put his mouth at Aziraphale’s ear. “I don’t want to ruin you.” He twisted his wrist and Aziraphale cried out without meaning to.
“Please, don’t stop,” he said. “You couldn’t possibly stop now.”
“Has anyone ever—”
“Not like this.” Aziraphale’s skin felt hot. He couldn’t regulate his temperature, he couldn’t regulate his perspiration. He didn’t typically perspire. He hardly knew what it meant to come apart in this very particular way. “You brought me here on purpose,” he gasped. “You did this.”
“You did .”
Crowley nipped at his mouth to shut him up. He’d lost his glasses at some point and his eyes were so very yellow and so very demonic, but also terribly sincere. “You’re not some run of the mill seduction,” Crowley said. “You’re so—you’re so much—“ he trailed off in a growl. It sounded pained and instead of trying to keep talking it seemed to focus him and he set about kissing Aziraphale and holding him close until Aziraphale could barely tell which direction Heaven or Hell resided.
“I’m.” Aziraphale felt his eyebrows draw together. “I’m quite close, if that’s—“
“Yesssss,” Crowley said. “Come on.”
Aziraphale did. He felt it rush through him, like his whole body was drawn up taut and then released like an arrow from a bow. He sagged into Crowley feeling like something monumental had just happened to him, and he supposed it had. Crowley was rutting against him, humping his leg were the fabric had been hauled up to reveal one of his soft, pale thighs. He could smell the whole city. He could smell the orgy going on inside the villa. But the most distinct smell of all was Crowley’s desire.
“There, dear,” Aziraphale said. His voice sounded rough. “Just like that.” He touched Crowley’s hair and his cheek. He kissed just beside his eye and braced himself against the railing, kept one leg pressed up and between Crowley’s two, and allowed him to take his own pleasure.
“Fuck,” Crowley groaned. “Fucking hell.” His breath was so warm and wet against Aziraphale’s neck, and his movements had become uneven and desperate. “Tell me—tell me it’s okay—“
“When in Rome.”
Crowley shuddered, he shook. He laughed helplessly and latched their mouths together again while he spilled between them, riding out the last of it on Aziraphale’s thigh.
They righted themselves when it was over. Aziraphale tugged his toga back into place and quickly miracled away the mess while Crowley resituated his silver leaves. They didn’t make eye contact.
“Angel,” said Crowley.
“Hmmm?” He occupied himself by adjusting the winged pin at his shoulder.
“Angel, we should talk.”
Aziraphale smiled. “Whatever for? Nothing happened.” It was for the best.
“Nothing at all. Shall we go back in? I think I saw enough for home office.”
He was too busy putting himself through a complicated series of mental gymnastics routines to consider whether it was best for Crowley. And he was equally too busy to catch the crestfallen look on Crowley’s face.
“And Crowley? We shan’t speak of this.”
And they didn’t. 
 Served with an Apician sauce of pepper, lovage, parsley, dry mint, malabar leaves, quite some cumin, honey, vinegar, and broth.
 Aziraphale wasn’t keen to admit that he even knew what Crowley looked like when he was about to make a point, clever or otherwise.
 Snakes run cold, demons run hot.
 He was looking forward to the advent of trousers, whenever that might be.
 Google it.
 On January 22nd, 41AD, to be exact. Crowley got at least one stab in.
 The next time they ran into one another at an orgy, Crowley gave Aziraphale the eye and Aziraphale pointedly looked away. Of course, that was only the next time and they had nearly 2000 years to follow and all the years thereafter.