Fort Collins, Colorado.
It was Christmas Eve and Sam and Dean were celebrating with Cas after taking care of a ghost that had been haunting a local bar. The ghost was that of a former regular who had gotten drunk one night before driving home - except he'd never made it there. He'd driven into a bus at 80 mph, and blamed the owner of the bar for not keeping his keys for him. It was a simple salt and burn job, but the bar owner was so grateful he'd offered them free drinks over the festive period.
Dean had been all to eager to take him up on his offer, and was currently singing along to The Darkness who were blaring out of the bar stereo. Thankfully he wasn't trying to shatter the beer glasses.
"Dust underneath the mistletoe leaves when you're not here!"
Sam scoffed. "More like drunk under the mistletoe," he muttered to himself. By his estimate (not that he was paying attention) at least half the girls in the bar had fallen victim to his charm and offered up their lips to him like lambs to the slaughter.
Castiel may have been sitting and conversing with Sam, but his attention was solely on Dean just now. "Dean has a lovely singing voice," he noted.
"He's not bad," Sam offered. "He sounds a lot better when he's sober, but he only sings in the shower."
"Oh, I know. I've heard him."
Sam inhaled a mouthful of beer and started choking.
"I've noticed that motel walls are perhaps not as thick as the should be, considering the late-night activities of many of their inhabitants," Castiel continued.
Sam said nothing, but returned his attention to his beer.
"Christmas time, don't let the bells end!" As Dean finished, he raised his glass in the air like a victory salute and sloshed beer all over his sleeve. Oh, yeah. He was good.
"Not bad," commented a woman he'd noticed watching him.
"Thanks," he grinned. "Oh, look. We're under the mistletoe." His words were innocent enough, but his tone was anything but.
"So we are," she agreed.
He slipped his free arm around her, fingers splayed across her lower back, and pulled her flush against him as she raised her mouth to his.
. * * * .
Periodically Sam looked over to check on Dean, and an hour later he realised his brother was swaying unsteadily on his feet. "We'd better go before Dean drinks the bar dry," he said.
Castiel looked at his watch. "It is rather late," he commented.
"You get Dean," he instructed, grabbing his coat from the back of his chair. "I want to have one last word with the owner before we go."
Castiel made his way over to Dean. "It's time we were leaving," he informed him.
"Heeey!" Dean greeted Castiel drunkenly, before he grabbed the familiar trench coat and pulled Castiel into a kiss.
When they parted he blinked, belatedly realising it was Cas he was kissing - Cas who was staring at him with wide eyes and flushed cheeks - and why the fuck was he kissing Cas? He started to stutter his way through drunken apologies, but then Cas shoved him against the wall and laid claim to him, the booze making it feel like his tongue was everywhere at once, and he decided that it didn't really matter.
Sam's jaw dropped when he looked over to see if Castiel had managed to drag Dean away from the mistletoe yet, because that was most certainly not what he'd expected to see. He groaned, because either he was going to have to play peace-keeper when Dean sobered up or the two were going to be grossly inseparable.
When Cas and Dean finally broke apart, and Dean staggered over to Sam who proceeded to complain (loudly) about being kept waiting, Castiel discreetly pocketed the mistletoe that had been hanging above their heads.