The first time Dean manages to persuade Cas to be his wingman, it's approaching midnight, the end to one of those days, and Dean is sitting in a seedy bar opposite a girl who is, on the surface, pretty much his idea of a perfect Friday night. When he'd first laid eyes on her about an hour ago, he'd made a mental note to congratulate Sam for setting him up with the hottest woman this side of Heaven, because seriously, Sam's track record with blind dates is absolutely terrible. In the space of about six months, Dean has been set up with two lesbians, one lawyer and three Romney supporters. He hadn't even known that they existed outside the grubby corners of the internet. He doesn't really know why he still lets Sam set him up, but it seems to make Sam happy, so he goes along with it. It's not like he can't find his own dates, thank you very much. In fact, he likes to think he's pretty adept at it. He might not be Casanova but he gets laid regularly enough and that's all that really matters in the short-term. He doesn't let himself think about the long-run.

This girl is an anomaly in that, until now, she'd seemed almost completely normal and entirely ridiculously hot. With bright blue eyes, long dark hair and a dress that clings in all the right places, she's totally Dean's type. Unfortunately, she's also apparently a complete moron. She likesTwilight, and worse, she's Team Jacob. She doesn't get Dean's Dr Sexy references. She hasn't heard of Led Zeppelin. Worst of all, she's spent the past ten minutes extolling the virtues of a vegan diet free from gluten and carbs. Dean is nodding around his mouthfuls of cheeseburger but he doesn't know how much longer he can stand to hear about what is essentially edible cardboard before he has to hurl.

Mercifully, God provides him with a window of opportunity. The girl – Brianna, she said her name was – puts down her fork, loaded with rabbit food, and blushes.

"Would you mind if I excused myself for a moment?" she asks. "I have to use the bathroom."

Dean nods, internally praising the Lord, and she smiles gratefully. "I'll only be a moment," she promises. Dean doesn't particularly want to hold her to that. As soon as she's out of earshot, Dean whips out his cell phone, which he's had hidden on his lap for the past ten minutes in preparation for a time such as this. He needs an out, and he needs it now. He's about to call Sam when he remembers that Sam is out of town on some pansy conference about feelings, the kind that don't involve penises, and curses under his breath. Who else can he call? He doesn't much fancy his chances of Bobby being sympathetic, and the ribbing he'd get for the next six months just isn't worth it. With Sam and Bobby out of the picture, that pretty much just leaves Cas. Dean is momentarily stunned at how few friends he actually has – two of whom are family members, at least by default – before deciding that hey, calling Cas is better than spending the next two hours listening to Brianna drone on about soy milk.

Cas, to his credit, picks up after the third ring.

"Hello?" he says, gruffly. Dean thinks that he sounds like he's just woken up, but then again, he always sounds like that, like he's been dragged out of some pleasant dream and isn't happy about it. "What do you want, Dean?"

"Cas, man, you gotta help me," Dean hisses. The pause that follows is so pregnant with confusion that Dean would laugh if this weren't a life or death situation.

"Are you in trouble?" Cas asks.

"Dude, so much," Dean replies. "Cas, you gotta be my wingman."

He can almost hear Cas furrowing his brow in complete 'does-not-compute' mode. The image makes him smile inexplicably.

"I do not understand," says Cas. "What is it that you want from me, Dean?"

Dean is sick of spelling everything out for the angel. Life is not an alphabet. This is not Sesame Street.

"A wingman, Cas," Dean sighs, exasperated. "You know!"

"I believe I have made it apparent that I do not. Unless you are referring to my wings, in which case, I am already - "

"It has nothing to do with actual wings, Cas," Dean groans. He's running out of time. "Look, forget the 'wingman' bit, OK? Here's what's going down; Sam has set me up on a date with this woman and she's a total psycho, man. She reads books about gay vampires and shit. I can't do this. I need you to phone me in like fifteen minutes, help me get away."

There is a short pause as Cas digests the information. Dean hopes he's getting it.

"What would be required of this phonecall?" Cas asks, carefully, and Dean knows he's hitting the home stretch.

"Just something that means I have to leave," Dan answers. "I don't know. Tell me my dog's died or something."

"But you do not have a dog," Cas points out.

"She doesn't know that!" Dean cries. The man on the table next to him gives him an odd stare. Dean gestures some uncoordinated reference to Cas' complete ignorance to the workings of society, and the man seems to get it.

"So, if I have understood you correctly, you require me to wait approximately fifteen minutes and then telephone you with the news that your dog has passed away," Cas clarifies. Dean nods, then remembers that Cas can't actually see him nod – or can he? He wouldn't be entirely surprised – and decides to verbalise.

"Yeah, basically," he confirms. Cas sighs.

"Have you not considered honesty towards the girl in question?" he asks. Dean snorts.

"Man, trust me on this," he says. "Honesty is never the best policy when it comes to dating."

From the corner of his eye he sees Brianna picking her way through tables of drunken truckers to reach him, and he steels himself for the most tedious fifteen minutes in living memory.

"Cas, I gotta go," he whispers. "But don't forget, yeah? I'm trusting you on this."

"I will not let you down," Cas promises. Dean hopes he's telling the truth.

Brianna reclaims her seat opposite Dean, picks up a forkful of disgustingly green stuff and offers Dean a mega-watt smile that he would find seriously attractive on a girl with half a brain.

"Where was I?" she beams.

"You were in the bathroom," says Cas, and Dean turns around sharply. Cas is standing behind him, his eyes narrowed in confusion. "Do you not recall?"

Brianna giggles nervously. Dean rests his head in his hands. He'd forgotten about Cas' angelic mojo teleportation thing. Normally, he thinks it's kind of cool, but right now? He just wishes he'd chosen a less socially awkward wingman. Still, at least Brianna will probably be sufficiently freaked that she won't ask for a second date.

"Sorry, but who are you?" she asks. Cas looks at her, blankly.

"Dean has a dog," he says. Dean wants the floor to open up and swallow him whole. Brianna looks at Cas, then at Dean, then back at Cas.

"OK," she replies, slowly.

"It is dead," Cas continues. He looks at Dean. "Sorry, Dean."

"Hey, man, not your fault," Dean mutters. Cas is about as smooth as sandpaper, he thinks. Brianna's mouth falls open slightly.

"Sorry, Dean, but who is this?"

Dean scratches the back of his head. Roommate, he thinks. That'll work.

"My roommate," he answers. Brianna raises an eyebrow.

"I take it you shared the dog," she says. She points at Cas. "He doesn't look too upset that it's dead."

Cas' eyes widen, almost imperceptible to those who don't know him as well as Dean. Well, shit. No-one expects the Spanish inquisition, thinks Dean, and he opens his mouth to explain, but Cas beats him to it. Dean's heart sinks in worried anticipation.

"The dog was named Mary, after Dean's late mother," Cas starts. "Dean has had the dog since he was quite young. I have only lived with Dean for four months, three weeks and six days. It did not seem pertinent to grieve for something that someone else loved more."

Dean stares. Brianna flushes and looks down at her salad.

"Sorry," she mumbles. Cas opens his mouth, clearly about to say 'and you should be', but this time Dean wins.

"It's OK," Dean says, breezily. "But, hey, is it cool if we call it a night?" He manages to make his voice crack audibly and praises his own acting skills. "That son of a bitch was all I had in the world. That female son of a bitch. Obviously."

Brianna pats his hand sympathetically.

"Of course, it's fine," she says. "You go and take care of what you need to take care of." She stands up, placing her hand on Dean's shoulder. "Call me?"

Dean nods.

"I will, definitely," he lies. Brianna smiles.

"Great," she says. "See you soon!"

With that, she leaves, and Dean breathes a sigh of relief. Cas looks at him. The man on the next table is staring at them weirdly and Dean sighs. He grabs Cas by the wrist and manoeuvres him into standing next to Brianna's now vacated seat.

"Sit down, Jesus," he says. "You're making the place look untidy."

Cas still looks suspicious, but does as Dean asks, reaching over to steal one of Dean's fries as he does so. Dean bats him away. Cas fixes him with a glare that clearly says 'I am having one and you cannot stop me', and Dean relents. He values his life and doesn't want it ended by an angel over a French fry. When Cas has finished chewing, he regards Dean thoughtfully, eyes as ridiculously blue and confused as ever.

"I still do not understand why you could not have told her that you wished the date to be over," he confesses. Dean offers him a fry and he takes it.

"I didn't want to sleep with her, Cas," says Dean, picking up his hamburger. He'd forgotten about that. That's worrying. It's not often Dean forgets about food. "But that doesn't mean I wanted to hurt her feelings. It's not her fault we were about as compatible as Bert and Big Bird. And yeah, I know you don't get that reference, but you get my drift, right? You gotta be cruel to be kind."

Cas nods slowly.

"I think I am beginning to understand," he says. "And this is what is meant by 'wingman'?"

Dean mumbles his confirmation around a mouthful of now lukewarm burger. Cas eyes the burger jealously and Dean sighs, setting it down onto the plate and wiping his mouth before offering the plate to Cas. His stomach feels odd, ostensibly with hunger, as he watches Cas' look of utter joy. He looks away.

"Dean, I think I would like to be your wingman," says Cas, finally. A small smile spreads across his lips and Dean's stomach protests its hunger again. "It is a fitting title for an angel."

Dean grins. He doubts Cas fully understands what he's let himself in for. Cas doesn't know Sam.

"All right," he says. He pauses. "But next time, just call, yeah? The whole 'beam me up Scotty' vibe might be a bit, y'know, obvious."

Cas nods.

"I am sorry," he says. "I thought it would be more convenient."

Dean feels guilty. He pats Cas' wrist in what he hopes is a reassuring way, ignoring the way Cas narrows his eyes.

"Cas," he says. "I have faith that you'll be the best wingman ever."

Of course, he'd be his only wingman ever, but that's a story for another day, when Dean's had a lot more to drink.

The next time it happens, Dean is entirely to blame. He can't put any of this on Sam. Dean had met the girl – Janet, what a name - last week while in possession of a spectacular pair of beer goggles and invited her for coffee – why had he done that? He never invites anyone for coffee, because seriously – and in the cold, sober light of day, it turns out that the girl has a pretty impressive moustache. It's not that Dean's shallow – well, not that shallow – but he draws the line at girls who have more facial hair than he does. As before, he waits for Janet to make her excuses and go to the bathroom before phoning Cas. Cas answers after the first ring this time, and Dean finds himself incredibly pleased by this.

"Cas, I'm in trouble," he says. Cas sighs audibly.

"Do you require my services as wingman?" he asks, as though 'wingman' is an official job with paychecks and a corner desk. Dean finds it endearing as hell.

"Yeah," he says. "You know the drill, right?"

"I believe I have sufficient recall to perform the task," Cas says drily. "I shall phone again in ten minutes."

"Thanks," says Dean. "I owe you one."

"Yes," agrees Cas. "You do."

When Janet returns, she orders another cup of coffee. Dean guiltily refuses, aware that he won't be here long enough to actually drink it. Janet is good company, and the ten minutes pass quickly, but Dean doesn't regret his decision when Cas calls. He lets it ring four times to feign ignorance of what's coming before answering.

"Yo, Cas," he says. "What's up?"

"I am calling to inform you that I have recently split with my long-term partner and require a shoulder upon which to cry," Cas answers, and it's so obvious that he's reading from a script that Dean has to fight back laughter. Drawing his features into what he hopes is a concerned rather than amused or constipated expression, Dean continues.

"Oh no, man, that sucks," he says. "Do you need me to come round?"

"Yes, Dean, that would be the point of this conversation," Cas says, impatiently. Dean hopes Janet didn't hear that. She's looking at him worriedly, her mug still in her hands.

"OK, OK, calm down. I'll be there in ten." Dean can see Janet's shoulders slump as she realises that the date is over.

"Thank you," says Cas, hanging up.

"No problem," Dean tells the dead line, and, putting his phone back in his pocket, fixes Janet with an empathetic gaze. He shrugs. "What can you do?" he sighs. "The man's a mess."

Janet sets down her mug, slightly sadly. Dean feels the old familiar tug of guilt at his heartstrings but ignores it. She has a moustache.

"You have to go?" she asks. Dean nods.

"Yeah, sorry," he responds. "That was my friend. His boyfriend just dumped him. He's a broken shell of a man."

He's not sure why he decided that Cas' non-existent relationship should be homosexual, but he rolls with it. Janet smiles softly.

"It's great that you're doing this for your friend," she tells him. "It's fine, I get it. You'll text me, right?" She looks hopeful, and Dean nods as he stands up.

"Definitely," he says untruthfully. "I had a nice time."

Janet looks happier at this, and Dean offers her one last consolatory smile before walking out.

Cas is waiting outside. Dean's heart flips. He supposes the guilt is tugging harder than usual.

"You owe me," says Cas. Dean shrugs.

"All right, I get it." Cas raises an eyebrow. " Just let me know when you need that favour calling in, yeah?"

"I will," says Cas, before promptly disappearing. Dean just stands there, shaking his head. He doesn't understand that angel.

It's a complete surprise when Dean's phone rings six days later while Dean's in the middle of a blazing row with Sam. Sam raises an eyebrow.

"You gonna answer that?" he asks. Dean growls.

"No, I was going to keep destroying you verbally," he retorts. Sam scoffs.

"Dream on, jerk."

"Maybe I will, bitch." Ignoring Sam's disgusted look, Dean looks at his phone. Cas is calling him. This is unusual; Cas hates phonecalls. His main philosophy in life seems to be why call when you can freak everyone the fuck out by teleporting? Dean finds himself glad that Cas is breaking with tradition. Cas always manages to cheer him up with his insane ineptitude. Or piss him off beyond belief. It's 50/50, really.

"Jesus, answer it," Sam moans. "Your ringtone is the most annoying thing since Rebecca Black."

Dean sticks his tongue out at Sam, who retorts by giving him a look of complete and utter revulsion, and answers the call.

"Cas," he says by way of greeting. "You interrupted me beating Sammy's ass into the ground with my words."

Sam barks out a huff of frustrated laughter.

"I did not mean to interrupt anything," says Cas. "I am merely calling to request the favour that you owe me."

Dean has to process that for a few moments before he realises what Cas is referring to and groans.

"Cas, man," he says. "I didn't think you were actually gonna hold me to that."

"You told me to." Cas' tone is clipped, and Dean knows better than to argue with that. He sighs.

"Fine. What do you want?"

"I would like to spend time with you," is Cas' answer.

"You spend plenty of time with us on hunts and stuff," Dean says. Sam raises his eyebrows and Dean turns away from him.

"I do not mean with you and Sam," Cas clarifies, and Dean knows he's probably imagining it but Cas sounds flustered. "I would like to spend time with you, Dean."

Dean's heart-rate suddenly seems to have increased to dangerous levels. He can almost hear Sam's gloating already.

"Why?" he asks. Cas doesn't respond for a few moments and Dean fears the worst.

"I do not read books about homosexual vampires," he replies eventually, and Dean is so screwed. "And I do not have a moustache."

Dean considers this. Of all the conversations he imagined having today, this isn't one of them. Actually, scrap 'today'. 'Ever' would be more appropriate.

Dean isn't gay, but when he thinks about it, Castiel isn't a man. Sure, he's got a dick, but he's pretty sure that Lady Gaga does too. He's not going to deny that he can appreciate the fact that Jimmy Novak was kind of a looker, if you're into that kind of thing, but dudes don't usually do it for him and he wonders if he can look past the fact that Cas' meat suit has a definite bulge in the trouser department.

Cas is pretty great. Dean owes his life to him.

"All right," he finds himself saying. "Fine. When?"

"Are you available from 8pm tonight?" asks Cas, sounding more cheerful than Dean thought possible for an angel.

"Yeah," Dean replies. "See you then, I guess."

"Yes," Cas confirms, and hangs up. Dean, who will never get used to Cas' telephone manner, stares at his phone in disbelief. Sam clears his throat.

"Sounds like someone's got a hot date lined up," he teases. Dean facepalms.

"I thought Cas would ask me to pick up something convenient, y'know, like demon blood or a child's soul. Not a date." He pauses. "Is it even a date? He didn't say the word 'date'. It might not be a date - "

"It's a date," Sam says, cutting Dean's babbling off. "He looks at you like you look at apple pie, and wow, that came out more adorable than I'd planned. Anyway, best get your glad-rags on and pick out an outfit."

Dean throws a cushion at him. Sam grins and leaves Dean to it, humming 'I'm Going Out Tonight' under his breath.

Dean swears that if he makes it to sunrise, he's going to kill himself.