When Dean returned to their room, six or seven beers down, the bathroom door was closed and the shower running. He kicked himself for not taking a piss back at the bar, or even in behind the bins at the gas station next door. Would have saved him this awkward situation.
He rapped on the door bashfully. "Hey, Cas?"
"Listen, I know you're prob'ly mad - hell, I would be, too - but I'm kinda drunk and I gotta take a piss, so..."
There was no sound from behind the door. Possibly Cas hadn't heard him, but ah, screw it.
"I'm coming in, okay?"
He pushed the door open (of course, an angel wouldn't think to lock it) and immediately wished he hadn't. Would've saved them both the humiliat- "Don't-" the angel warned, and oh God, he was crying. Cas.
"No, don't. I'm - sorry, I..." Castiel babbled as he tugged at the shower curtain, trying to hide himself from view, but it was too late - Dean had seen. The goosebumps on his skin, the tears on his face, the borrowed clothes strewn dejectedly on the floor, sopping up the water that collected there from the streaming showerhead. Dean had seen it all, so there was no point in leaving a weeping angel - no, his friend, this was Cas - trapped mid-meltdown behind a plastic curtain.
But what the hell was he supposed to do, here? They weren't exactly champions at this heart-to-heart shit, at least not like this. He took a long, deep breath, exhaling as he relieved himself, trying to ignore the soft hitching sounds of breath that issued from the angel's hiding place. He flushed the toilet, zipped his pants, and ran his hands under cool water, all the while grasping at straws for something to say to the guy. In the end, he had nothing, so Dean bit back a grimace as he drew back the shower curtain and looked upon Castiel.
"Hey." Dean forced a touch of lightness to his voice. "What'cha doing in there?"
Cas sniffed and scowled. "I was trying, as you suggested, to - " he waved a hand in the air dejectedly " - bathe myself." Dean had to stifle a snigger, and the angel glared at him before averting his eyes in shame. "... I don't know how."
"Yeah, um..." The floor was slick with icy water. "I can see that."
Cas let out a quick, heavy breath, something between a laugh and a sob, before drawing his knees up to his chest and burying his face in his hands. He took one, two, three deep breaths in silence before Dean thought he should - "Cas?"
"I am trying, Dean." When the outburst came, it was harsh and erratic, and Dean couldn't remember seeing Cas so upset. "I'm trying to adjust to living - like this, but you see, it's just impossible - " He took a moment to breathe, to find the words. "I can't contain my thoughts, but there's nowhere to go - My vessel, my - me, it aches, and tires, and I don't know how to think, or how to stop, or how to - I can't be such a burden to you, Dean, it's... degrading." He spat the last words before collapsing into tears once more, grasping at his ankles tightly as he tried to reclaim control.
Dean was struck silent by Castiel's words, immobilized by the knowledge that he just didn't know how to respond. The showerhead still spewed cold water - dumb angel hadn't set the knob to run hot - and Cas, he saw, was shivering. The last beer or two grumbled in his stomach and sent a fizzy wave of tingly warmth through his body. Stupid, really, that the two most screwed up dudes in this whole world (barring Sam, wherever he was) had somehow wound up stuck together. Bound, Cas would call it, and that always made him chuckle uncomfortably -
Dean adjusted the shower knob and grabbed a tiny hotel shampoo. As the water heated, he could see Castiel's sobs subside, the shivers slide away, as his grip on his ankles loosened perceptibly. Dean took a handful of shampoo and gingerly worked it into Cas's hair, and when the cool gel touched his scalp, the not-quite-angel startled anxiously.
"Um, what are you doing?"
It wasn't accusatory, just that same annoyed naivete at which Cas was so accomplished, surely a sign he already felt better. Dean sighed and held up the bottle.
"This is shampoo. It goes in your hair. The idea's kinda - weird - so I'm just gonna show you."
Cas grunted in wary assent, slowly softening again as Dean worked the shampoo into his scalp. "Don't get it in your eyes," he warned, scrubbing playfully at the hair behind his ears and around his temples.
"Why?" Cas rumbled, closing his eyes and relaxing into Dean's touch.
"'Cause it stings like a bitch, trust me."
Dean rinsed his soapy hands in the stream from the shower, then grabbed a washcloth and a bar of soap.
"Soap," he explained, demonstrating as he worked the suds into the cloth, "is for your skin. Not your face, not your hair."
"Hmm." Cas withdrew his focus, squirreling away the knowledge somewhere for future use. Dean used the washcloth to scrub gently at the muscles on Castiel's shoulders and neck. He sponged down Castiel's arms and back, and when he feared Cas had gone too silent, he gave one shoulder a firm squeeze, shaking some of the tension from the angel's newly human vessel.
"Shh. Here." Dean passed off the washcloth. "Why don't you soap down your... rest of you, and I'll start rinsing out your hair?"
Cas complied, scrubbing at his legs & chest with a far-away look on his face. Dean focused on his hair instead, carefully rinsing away the shampoo the way he used to do with Sam. He'd barely noticed when Castiel's arm fell slack, the washcloth drifting forgotten in the shallow bathwater.
"I'm sorry if this is - uncomfortable - for you." Cas murmured.
"I know you don't like this kind of intimacy."
"Yeah, well..." Dean brushed away the jab as he finished rinsing out the shampoo and shut off the water "Who else is gonna show you the ropes?"
A tiny smile twitched upon Castiel's face, and Dean felt a grin creeping up on his as well. This was better. Still -
"I'm sorry about all this, Cas. I know it isn't what you wanted."
Cas shook his head dismissively. "No, I - I'm sorry I can't be of more use to you. Until we find Sam, that is..."
"No, listen, man." Dean interrupted in frustration, "Don't worry about that, not right now. Let's just get you up on your feet a bit." He took a deep breath and averted his eyes as he pulled a fresh towel off the rack. "I mean - I'm sorry about, you know, falling, leaving Heaven. It must be tough for you."
He gently tossed the towel into Castiel's lap. The no-longer-angel looked at it distantly for a moment before drawing it to his chest.