Notes: "Hello! Can you do a Pre-kerberos fic with pining! Shiro or mutual pining? I love Pre-kerberos fics they give me life"
Thank you operationkuro for the prompt!
Title taken from OuaT

If you had asked Shiro when he fell for Keith, he wouldn't be able to give you a definitive answer. It was a gradual build up, perhaps, filled with late night study sessions, inside jokes with gentle nudges, and whispers under the stars.

But mostly, it was the fluttering feeling in his stomach when he saw that beautifully undone mop of black hair or the violet eyes that only smiled for him. It was the electrifying touch of Keith's palm against his arm, and the yearning to take that hand in his own.

Shiro was not a man of impulse. He was collected, made decisions based on logic and reasoning. He was able to resist the pull of his feelings for the greater good, but lately it seemed like Keith's gravitational pull was changing his orbit.

"So when are you finally going to ask him?" Matt asked as he lay across his own bed, stirring Shiro out of his thoughts. Both of them were studying for the midterms that were coming up next week, and Shiro was lucky that his roommate was as studious as he was. Only the best were going to be selected for the Kerberos Mission next year, and both were eager to earn spots. Still, the casual tone of his friend did nothing to hide the implications of his question. Shiro had been pining for months, and Matt had done his best to build up his friend's confidence in asking his crush out. He knew Matt was getting tired of the whole ordeal—frankly, Shiro was exhausted of the force of withholding his own emotions—but Shiro had never asked Matt to get involved. He hadn't even told him about his intense feelings for the talented fighter pilot, but he figured he didn't have to. His soft gazes and gentle smiles spoke volumes. Still, Shiro refused to acknowledge it aloud. It would only solidify what he already knew: Keith would never see him as anything but a friend, and Shiro couldn't get in the way of Keith's potential.

"Matt, not now." Despite his tired and bored tone, Shiro's heart still went pitter patter at the thought of the talented pilot. He hadn't been able to spend much time with Keith since midterms were approaching, and they were both studying fervently to pass with flying colors.

With a sigh, Matt closed the textbook he was reading and sat up, aiming a speculative eyebrow in his friend's direction. "Seriously, Shiro? I don't know what the problem is. You like him, and he adores you. So stop this sacrificial martyr crap and just ask the guy out. Heck, you don't even have to use the word 'date.'" Matt's face slowly melted into one of concern, looking Shiro in the eyes when he gently said "You've been miserable these past few days, and it doesn't take a genius to know it's not just stress because of exams. You miss him."

Shiro couldn't debate that. He did miss Keith's devilish smirk and the gentle way he swept his raven hair out of his eyes. The cadet was a light in his otherwise routine life, and he made Shiro feel more alive then he'd felt in a long time. "I do miss him," Shiro admitted aloud as he turned back to the worksheets he was studying on his desk, "but I don't want to interrupt his studies. He's got a lot of potential, and I don't want to get in the way of that."

The sharp scoff from across the room made Shiro turn back around, glaring at the pointed look his friend was giving him. "Are you serious? If he's acting anything like you, he's not focusing on his school work because he's too busy pining. Just take a quick break. Go visit him, it'll probably brighten his evening."

The idea was tempting. Just a quick visit to Keith to say hello, and then back to studying. Shiro tossed it around in his head for a few seconds, until finally caving. "Fine. You're right. Maybe a little break would be the best for both of us." He pretended not to see Matt's eye roll as he got out of his desk chair.

"Oh!" Matt interjected, a smug look barely readable behind his casual façade. "Don't forget to bring your textbooks and work in case you're there for a while." Shiro shot him an unappreciative look. "You know, just in case he needs help studying or whatever" Matt amended innocently.

So that's how Shiro ended up standing in front of Keith's door, textbooks in arm, knocking hesitantly. He ignored the butterflies in his stomach, and the way his hands clenched his books in anticipation. 21 hours. That's how long it had been since he had last seen Keith. He wasn't sure if he was ready.

When Keith finally answered the door with a confused face that instantly morphed into one of pure joy, paired with a radiant smile, Shiro knew he was a goner. And if Keith's amazed voice and sparking eyes when he gasped "Shiro?" made his heart melt into his boots? Well, no one had to know that.