Just an idea that hit me the other day that I decided to jot down...contains very tame slash. Enjoy :)

"Aziraphale?" Crowley said.

Aziraphale, who had been caught up in explaining all the possible ways one could turn an unwanted pregnancy into a life-changing blessing, looked a bit started at realizing that Crowley was still sitting next to him. "Yes?"

"Have you ever sinned?" Crowley asked.

Aziraphale immediately drew himself up, the very picture of angelic posture. "I should say not!" he responded indignantly.

"I thought pride was a sin," Crowley remarked, glaring at a couple on the bridge. The man was on one knee, holding out a ring to the woman. She reached out to take it, and it suddenly slipped from the man's fingers and fell into the water.(1)

Aziraphale didn't notice. He frowned. "Pride in one's successful angelic duty is not a sin," he said, though he sounded a little uncertain. "In fact, I should think that—"

"Yes, yes," Crowley said, waving a hand impatiently. "I'm sure that's all very well and good. But. I thought Jesus was the only guy who never sinned."

"The only human," Aziraphale corrected primly. "Angels can't sin."

"Ever wanted to try?" Crowley asked.

"Angels aren't tempted to sin, either," Aziraphale said.

"Yes, but," Crowley pressed on, "Demons aren't supposed to do good, and I plotted with you to foil the Antichrist from destroying the world."

"I thought we agreed that was part of the ineffable plan, my dear," Aziraphale said.

Crowley gave an irritated huff. Angels were so dense. He looked around, spotted a man about to abduct a two-year-old, and blinked. The man suddenly remembered that he had left the oven on and rushed away. Not the most original, of course, but hey, he wasn't exactly used to this.

"There," he said. "I just stopped a kidnapper."

Aziraphale smiled happily. "I told you there was a spark of goodness in you," he said.

Crowley rolled his eyes, thinking about how he was going to explain that particular miracle, anyway. "Step in the process of tempting an angel to sin," or something. More formal sounding, when he had the time.

"That's not the point," Crowley said. "The point is if I can do good, you can sin."

"You were an angel once," Aziraphale pointed out. "The ability is inherent in you, even if it's forgotten."

Aha! Crowley knew he had the argument won, now. "Then it goes both ways," he said. "I was created an angel, but I can sin, which means that all angels have the ability to sin, they just don't realize it. And, since you're living in a human body—"

"Angelically crafted," Aziraphale pointed out.

"Yes, yes, but it can still die, can't it?" Crowley continued. "You're pretty much just showing Jesus up, aren't you? By not sinning? I'm sure his body was divinely crafted, as well. I mean, how else did he get through puberty without ever—"

"My dear boy," Aziraphale said, sounding testy. "Please get to your point."

"My point is that you should try sinning, just once. Otherwise, how can you be so against it? And if you know it better, you can thwart it better."

Aziraphale paused, mulling that over. "You do have a point…" he said slowly. "Maybe just a little one wouldn't…"

"Brilliant!" Crowley said with a grin, and without any further warning or delay, he leaned over and kissed the angel full on the mouth.

Aziraphale didn't pull away, but he didn't exactly respond, either. He just passively followed the kiss through its course, then leaned back when Crowley did, looking puzzled.

"There," Crowley said smugly.

"But, my dear, that wasn't a sin," Aziraphale said.

Crowley's jaw dropped. "What? But your lot and their whole gay-hating thing—"

"Oh, that," Aziraphale said dismissively. "That's just a rumor." He paused and looked at Crowley. "We thought that was you."

"How could it be us?" Crowley asked. "The Christians are the ones perpetrating the whole thing."

"I know," Aziraphale said glumly. "It's quite hateful of them. We thought it was your lot trying to distract them."

Crowley shook his head. "Humans," he said, a note of admiration creeping into his voice. "The things they come up with."

Aziraphale nodded in agreement. "It's the Evangelicals," he said.

"They're like Satanists," Crowley said. "Can't do anything because they're loyal followers, but boy what a pain in the ass they can be…"

"Ineffable pains in the ass," Aziraphale agreed.

Crowley hm'ed. He hadn't given up on his mission to get Aziraphale to commit a sin. An idea occurred to him and he looked at the angel with a smirk. "Well, if gay kissing isn't a sin, what about premarital sex?"

(1) A week later, a homeless man found the ring when he cut open a duck. He sold it for more than it was worth, bought a suit and a shower, and miraculously got the next job he applied for. Luckily for Crowley, Hell hadn't bothered to follow the miracle through that far.