Cooper sits in the kitchen in nothing but boxers, eating a slice of toast while he waits for Blaine to get home from school. Their parents are halfway across the world on a European cruise, and as much as the brothers insisted that the seventeen year old would be fine on his own for two weeks, they refused to leave Blaine home alone.
"It's the gay thing," Blaine had murmured miserably as the two of them went grocery shopping a few days before their parents left. "They won't say it, but they don't want me being inappropriate with someone under their roof."
"So you have a someone, huh?" Cooper had replied, cracking a suggestive grin.
"That's not what I meant."
"But you do."
"I … yes. His name is Sam," Blaine had admitted with a blush.
"Seven and a half months."
"Not what I meant, B," Cooper had joked with a wink.
Blaine had let out a scandalised, "Cooper!" and refused to talk about Sam with Cooper from that point onwards. Cooper tried, but Blaine blushed and refused to co-operate every time he mentioned the boyfriend. But Cooper would see him sometimes, sitting on the sofa with his phone in his hand and a soft smile on his face, or coming home after a day out with a spring in his step and his cheeks flushed, and it takes all of about two days for Cooper to realise that Blaine is really smitten with this kid.
So when the front door opens and Cooper hears not one set of footsteps but two, he works out pretty quickly that he's brought this Sam kid home. They're talking animatedly as they walk hand-in-hand into the kitchen, and Blaine's so caught up in conversation that he doesn't notice Cooper at the breakfast bar in the corner.
Sam's cute, Cooper decides. He's got lips too large for his face and bright blue eyes that look like they belong on a newborn baby, but it works. And if his roots are any indication, he dyes his hair, but that just adds to the whole 'cute' vibe Cooper's getting from him. Straight or not, Cooper can see the appeal, and he leans back in his chair with a smirk on his face as he watches them interact.
Blaine's still caught up in whatever he's talking about, mouth moving quickly and hands flying around to emphasise his words. When he pauses mid-rant to take a sip of the orange juice he just poured, Cooper speaks up.
"Damn, Blainers actually caught a looker."
Blaine chokes on his orange juice in surprise and Sam blushes, smiling bashfully at Cooper as he pats Blaine's back.
"Cooper!" Blaine hisses once the coughs have subsided, red in the face with embarrassment and clenching his hands into fists uselessly by his sides. "You- I- You're not meant to be here."
"Where am I meant to be?"
Blaine splutters at that. "I- somewhere- I don't know. You're Cooper. You always have somewhere to be."
"When I want to get out of family dinners, yes, I always have somewhere to be," Cooper retorts with an amused smile, leaning forward on the counter. "But I'd be a very irresponsible babysitter if I up and left you, now, wouldn't I?"
"I thought we agreed not to use that word," Blaine groans, leaning against the counter with a huff. "Can you, like, leave?"
"I'll put music on if you don't want me to hear you two fucking. Hey, maybe I'll even try not to walk in you."
It's Sam's turn to splutter and Cooper grins at him mischievously until he looks away, rubbing his neck. Blaine huffs.
"I wanted you to leave before you embarrass me, actually, but clearly it's too late for that. We have a science project to get done-"
"Biology or Chemistry?" he teases, and he feels pretty proud of the comment when Sam snorts in spite of his embarrassment.
"We're going to go now," Blaine says firmly, gritting his teeth. "We'll be upstairs. Walk in and I'll kill you."
Sam follows silently as Blaine begins to leave the room, and Cooper holds his hands up in defeat.
"What, you're not even going to introduce me to your boyfriend? Where are your manners, baby bro?"
Blaine hangs his head and turns around. "Cooper, Sam. Sam, the most annoying person you'll ever meet." He waves a hand between them. "There. You've been introduced. We're going now. Oh, and Cooper?"
"Put some clothes on, would you?"
Before Cooper can reply, Blaine laces his fingers with Sam's, shoots him an apologetic look, and pulls him up the stairs. Cooper feels content with himself as he finishes his toast and puts his plate in the sink, his big brother duties thoroughly fulfilled for the day.
Still, as he walks past Blaine's room on his way to the bathroom, he can't help but yell, "Get some, kiddo!" through the door. He hears Blaine groan something in annoyance but Sam's loud laugh quickly drowns out his brother's voice.
Yeah, Cooper definitely likes this kid.
He spends the rest of the afternoon in the spare room, just across the hall from Blaine's, and browses the internet to pass time. Even through two walls and closed doors, he can hear Sam and Blaine talking. Not enough to pick out words, but just the muffled noise of their voices. Blaine laughs a lot, loud and bright, and it's everything Cooper's been missing since Blaine was just a kid.
He smiles fondly at his computer screen as he listens to them, and even though he can't hear the conversation, he can hear the genuine happiness and excitement in his brother's voice. It's enough to make him officially approve of Blaine's relationship with this Sam guy.
Things get quiet in Blaine's room after a while and Cooper's smile turns into a mischievous grin. He leaves it a few minutes before sliding out of his room, still in nothing but boxers, and presses an ear to Blaine's door. Before long, he hears his brother sigh Sam's name, and he knows he has them right where he wants them. Blaine will kill him for interrupting but it'll be so worth it.
Big brother duties, right?
He puts his hand on the door handle, pausing for another moment before letting it swing open. He acts oblivious, starting to say "Hey, Blaine, I-" and promptly cuts off when he sees the boys, pretending to look shocked.
They're on the floor, Blaine propping himself up on his elbows with his head lulled back and his lips parted. Sam's lying on his side next to him, one leg slotted between Blaine's and his hand on Blaine's chest as he kisses his neck. When they hear Cooper, Blaine pushes Sam away with a groan and throws the first thing he grabs at his head.
The nearest thing to Blaine happens to be a thick Chemistry textbook and Cooper ducks away instantly, laughing and holding his hands up. Sam's blushing again, looking between the brothers awkwardly, and Cooper gives him a smug grin.
"Hey, Sam," he says, and Sam gives an awkward wave.
"Cooper. You know I love you. But I swear to God, if you don't leave us alone, I will call Dad and tell him the real reason you got sent home from summer camp when you were fifteen."
Cooper looks down at his brother with narrowed eyes, but Blaine just raises an expectant eyebrow. "Ugh, I'll be downstairs. You suck." He fights the urge to add Sam's balls to the end of the sentence, leaving the door open as he walks out. He can't stop himself from yelling, "Use condoms! And lots of lube!" over his shoulder, though.
Blaine opens the front door, leaning against it and looking out at the darkening sky. Sam takes his hands and he looks back, smiling softly when he makes eye contact with his boyfriend.
"You sure you're gonna be okay heading back by yourself?"
Sam chuckles and rests his forehead against Blaine's. Blaine's heart warms at the gesture.
"You're worse than my mom, Blaine. I'll be fine."
They grin at each other for a moment and Blaine squeezes Sam's hands, lacing their fingers together.
"I just really care about you," Blaine says softly, looking up at him.
"I'll be fine, babe," Sam repeats, laughing quietly and ducking his head to press a chaste goodbye kiss to the corner of Blaine's mouth. Blaine responds instantly, slotting their lips together and kissing him properly. Sam pulls back after a moment and Blaine chases him without hesitation, kissing him again. Sam laughs against his lips and a comfortable silence settles between them.
"I'm sorry about my brother," Blaine says eventually.
Sam shrugs and smiles. "It was kind of funny."
"It was mortifying," Blaine insists, wrinkling his nose.
"It's like a big brother code of conduct that you've gotta tease your little siblings. Seriously, I do it all the time. At least he's not like your dad though, right? If Cooper had a problem with our relationship, he wouldn't tease you."
Blaine smiles fondly, kissing Sam again. "I guess you're right."
"Of course I am," Sam says, grinning down at Blaine smugly.
Fifteen minutes later, Blaine finally closes the door and leans against it, sinking to the floor with a fond smile on his face. Cooper raises his eyebrows slightly. Seven months into a relationship and the kid can still make Blaine act like that? Damn.
Cooper puts another smug smirk on his face and steps forward from where he'd been lingering in the kitchen, but Blaine's eyes are closed so he doesn't see him approach.
"Well, he's cute," Cooper says casually and it startles Blaine so much that he hits his head on the door as he jumps. Blaine huffs, rubbing his head as he stands up. "And funny. And apparently has kisses to die for, if the way you just sucked his face for fifteen minutes is any indication."
"Anyone would think you were the one that's in love with him," Blaine grumbles as he heads into the living room.
"Nah, just letting you know that I approve. He blushes a lot, though. Might want to work on that in case Dad ever catches you, because you won't be able to pretend you were just studying if he's blushing like a Victorian schoolgirl."
"His blush is cute," Blaine mumbles defensively, sitting on the couch. "So … you like him?"
"He seems like an alright kid," Cooper says as he leans against the door frame. An alright kid that makes you happier than anyone else ever could, he adds internally. Not that he'd ever say that outloud though, because hello, sentimental much? He doesn't need Blaine thinking that he's going soft.
"I really love him," Blaine says quietly, staring at the wall vacantly with a small smile on his face.
"I can tell," Cooper replies softly, then quickly adds, "It's pretty sickening."
"I thought you approved."
"I do. Doesn't mean I want to listen to your lovesick rambling all night, man." Cooper knows he could listen to it all freaking year if he had to, but what Blaine doesn't know can't enlarge his ego. "Hey, I'm gonna heat up some pizza for dinner. That okay?"
"Sure. Can we watch Avatar?"
Cooper raises his eyebrow. "I thought you thought Avatar was boring."
Blaine bites his lip to hide a smile and looks away. "It's Sam's favourite."
"Aye, God!" Cooper exclaims, throwing his arms up in mock exasperation. "It's worse than I thought!"
Blaine shakes his head with a grin. "Dork."
"Loverboy," Cooper retorts, sticking his tongue out at his brother before disappearing into the kitchen.
"Asshole!" Blaine yells after him.
"Cocksucker!" Cooper yells back.
"That insult doesn't really work on gay guys, Coop!"
Cooper huffs. "Well it's true!"
Blaine's laughter fills the house and Cooper decides that, yeah, this Sam kid is definitely a keeper. It's been such a long time since Blaine's laugh was that loud and Cooper really doesn't want him to go back to the bottled up father's pet he used to be. Anyone that makes Blaine that happy definitely earns Cooper's gold star of approval.
Four for you, Blondie. Four for you.