It's not like they hadn't discussed it before, what Dean would think if he knew. They had. On multiple occasions. Beginning with the first kiss, when they vowed to not let it go any further because Dean probably wouldn't approve. And they meant it, too. Until the next kiss, when they re-iterated that they could not let it happen again. And then again, the next kiss. And every kiss after that. The conversation was always the same. "We shouldn't be doing this."
"I know."
"Dean…"
"I know."
With every word, the kisses grew deeper, their tongues entangling, twisting, biting, tasting. As if they fact that Dean would not approve suddenly made this kiss—the last one they would allow themselves to share—that much more urgent.
It always ended the same way, with one finally pushing the other one away leaving both flushed and breathing heavily. "Dean," they both would say, retreating to separate rooms or, if that wasn't possible (like the time Dean was in the shower and there was no separate room to retreat to), Castiel would just disappear entirely until they both had themselves under control.
They brought it up again during the first heavy petting session, when neither had been able to find the willpower to stop at kissing and Sam was shoving down Castiel's pants, grinding his bare cock against Cas's.
"God Cas…you feel so fucking good," Sam growled.
"We shouldn't be doing this," Castiel responded, lifting his hips. Their motions were desperate now, both searching for more. More movement. More friction. More of each other. "Sam…"
"I know," Sam whispered, pushing Castiel against the wall and taking their two cocks in his hand.
"Sam," Castiel growled. Sam's hand was pulling against them both as he tugged upward, flicking his thumb over the end of Castiel's cock. Castiel whimpered, thrusting his hips into Sam's grip, urging him to move faster. Sam just tightened his grip and continued his slow, agonizing descent. "Sam…" he managed to bite out. But that wasn't what he was trying to say and they both knew it. "Dean…"
"I know," Sam answered, crushing Castiel's mouth against his, tongue demanding entrance as his lips continued their bruising assault on Cas's. As Sam again began grinding against Castiel, they both lost the thread of the conversation entirely. Castiel entangled his hands in Sam's hair, pulling him deeper into the kiss and they both gave themselves over completely to the sensation of pressing against one another, Sam's hand moving in concert with his hips as he thrust against Castiel.
It was only after they were calling out the other's name, climaxing for the first time with one another and falling together on the bed, legs entangled, breathing heavily, that the subject again came up. It was once again Castiel who brought it up. "Dean," he managed to croak out.
Sam sighed and pushed Castiel away, running a hand through his hair. He stood up and headed toward the bathroom of the motel room. "I KNOW," he snarled, slamming the door behind him just as the unmistakable roar of the Impala announced that Dean was home. Castiel sighed and disappeared.
The next time they were alone together, they stayed on opposite sides of the motel room while they talked. They needed to stop, they agreed. While Dean wholeheartedly supported the idea of Sam getting laid, and he was even tried to arrange Castiel's first time, he would not EVER be okay with the two of them taking care of each other's needs. Whatever was between them wasn't worth risking the relationship each had with Dean.
"It's probably just best if I don't come around for awhile," Castiel said, trying to catch Sam's eyes. But Sam was looking anywhere but at Cas, certain as he was that Cas could actually read his thoughts when he had Sam's gaze.
"So that there's no temptation," Sam agreed.
Castiel did stay away after that. At least for awhile. For almost a month, he managed to busy himself with other pursuits and Sam managed to convince Dean that Cas wasn't needed on one hunt after another.
Sam was in the shower, washing away the dirt of a grave that he'd just been desecrating. Dean was outside, watching a movie while he waited for his own turn to clean up. As they always did while he was in the shower, Sam's thoughts turned to Castiel. He was picking up a bar of soap to slick up his hand and take care of the hard-on that always popped up every time he thought of Cas when there was a rush of cool air in the bathroom.
"Dammit, Dean!" he growled flipping around to hide his current state from his brother. "It's not bad enough that we spend 24 hours a day together, I'm not entitled to ten minutes alone in the bathroom?"
There was no answering retort, no flush of the toilet so that the water would run cold, none of Dean's usual hi-jinks when he wanted to send Sam the message that he was taking too long. Instead, the shower curtain slid aside and Sam found he was no longer by himself in the shower. Before he could open his eyes or otherwise figure out what was happening, a hand was wrapped around his aching cock and the low growl of Castiel's voice was whispering, "Wouldn't you rather I take care of that?" in his ear.
"Dean," Sam managed to get out before he abandoned all objections and gave himself over to Castiel's ministrations.
"So beautiful, Sam," Castiel said. "Couldn't stop thinking about you. You're not mad, are you? Couldn't stay away…"
He trailed off as Sam buried his hands in Castiel's hair and forced his lips against Castiel's, then drew back and met Castiel's gaze. "Not mad…God, Cas," he bit out. "Waited so long…" And then once again captured Castiel's mouth with his own, demanding entrance as Castiel obediently opened his lips, their tongues entwining, retreating, lips drawing back to suck and bite before their tongues met again.
Sam's hands explored every inch of Castiel's chest, finding his nipples and flicking over them. Castiel groaned and grabbed Sam, pressing him up against the wall and making a trail of kisses down his chest, stopping at the nipples to suck and bite at each until Sam was writhing, begging Castiel to go lower. Castiel smiled up at Sam before dropping to his knees, fingers trailing from Sam's chest to his hips. Castiel licked over the head of Sam's cock as Sam tangled his hands in Castiel's hair, forcing Cas's mouth against his cock.
"Sam?" It took Sam a split second to realize that the voice hadn't been Castiel's. "Thought I heard someone in here." Sam's panicked gaze met Castiel's. "You okay?" Castiel closed his eyes to prepare to disappear but before he could the shower curtain opened. Dean's eyes widened as he took in Sam, then Castiel kneeling in front of him. "Jesus Christ Sam!" Dean whirled around and flew out of the bathroom.
"Shit, shit, shit!" Sam said as he grabbed a towel and started to dry off.
Castiel didn't move. "Should I go?" he asked Sam.
Sam stopped in the middle of furiously drying his back and stared at Castiel. "Go?" he said. "He already knows now, Cas. What's the point of you leaving?"
Castiel nodded and stepped out of the shower. By the time he reached the bathroom door, he was dressed again, in spite of the fact that Sam hadn't actually seen him put on any of his clothing. "I guess we're going to find out what Dean thinks about all this," he said matter-of-factly then walked through the door and took a seat across from Dean, who didn't say a word. Sam finished getting dressed, took a deep breath and joined his brother and Castiel in the room.
They sat for a moment in awkward silence before Dean finally spoke. "You're not going to go soft now that you've found domestic bliss are you?" he asked, smirking. "Now that this is all out in the open, can we stop the ridiculous sneaking around and get back to hunting?"
Sam and Castiel exchanged a glance then both returned their gazes to Dean. "You knew?" Sam asked.
Dean rolled his eyes. "Of course I knew, Sam," Dean said. "You really think you can hide something like that from me? Come on."
"How?" Sam demanded. "We were careful…"
"Hope you were," Dean said. "Just because he's an angel doesn't mean you shouldn't be protecting yourself."
Sam sat back. "How?" he asked again.
"I'm not a total idiot," Dean retorted. "You two were acting like a couple of fifteen year olds who were scared Daddy wouldn't approve of the boy you were dating."
"So you're totally okay with this?" he asked.
"Since when have I ever given a crap about who you're sleeping with, Sam?" he asked. "Don't get me wrong. I'd have preferred not to witness the act but now that it's all out in the open maybe you two can get your heads back in this hunt and give me some help catching this thing."
"We're not sleeping together," Castiel interjected. "At least…not yet."
Dean stood up. "I didn't need to know that either, Cas," he said. He walked over to where Castiel was standing, on the other side of the room from Sam. "I'm not interested in the intimate details. All the same, Sam's still my little brother, Cas. You hurt him, I'll kill you." Dean shrugged his jacket on and walked over to his duffel bag. He rummaged around in it awhile before holding up a clean sock. "I've seen all I want to see of the two of you together," he stated. "Please put this on the door when you need some privacy from now on?" He tossed it at Castiel, who instinctively reached up and caught it, then opened the door and left.
Castiel stared after Dean for a second before turning to face Sam, who was now laughing. "Well, that went well," Sam said.
"Well?" Castiel responded. "He threatened to kill me. I wouldn't refer to that as 'well', Sam."
"Don't worry about it, Cas," Sam said, walking over and wrapping his arms around Castiel's waist and drawing his body against Sam's own. "It's what humans do when they care about someone." He leaned down and brushed his lips against Castiel's then took the sock from him and walked over to the door and opened it, placing the sock on the handle before closing it and returning to where Castiel was standing. "Now, where were we?"
After, when they were lying sated in the bed, arms and legs tangled around each other, Castiel's head nestled against Sam's chest, Sam realized that Dean had been right. He may not have the house or the white picket fence or 2.3 kids. The man he was in love with might be an angel. But he had found domestic bliss. Or, as close to as a Winchester could ever hope to get, anyway.