Saw Big Hero 6 and this was probably the first impression I got when seeing the two boys interact. I tried finding some other fics, and while there are some, they're not quite what I was looking for. I prefer a story that talks about how they first get together, rather than the story starts off and they're already 100% comfortable with each other's naked bodies. So here's my story; Hope you enjoy it!

Tadashi quickly picked up his room as he got ready for bed. Making sure his space was clean was really the only way to stay sane when sharing a room with you brother for over ten years. The black-haired young man surreptitiously glanced over at his younger brother. Hiro was laying on the floor with his feet raised up on his bed, staring at the ceiling in an almost catatonic state.

Tadashi walked over and looked down at him. Hiro barely registered that there was now a face blocking his view.

"Okay, what is it this time?" The older brother always tried to keep a peppy tone in his voice when speaking to Hiro. It seemed to help connect with him sometimes.

The teen let out a melodramatic sigh. "Booored..." he groaned.

"It's almost time for bed. You want to watch a show with me?"

Hiro's eyes finally focused on his older brother's hopeful face. With a sigh and an eyeroll, he flopped to his side and clambored to his feet. "Yeah, sure."

"I'll set things up. Why don't you go nab something from the kitchen? Aunt Cass had that batch of donuts that didn't turn out quite right..." Tadashi smiled as he watched Hiro's face light up. While the short teen went rushing downstairs to get something to eat, Tadashi finished cleaning up the room and prepared his tablet for their show.

Tadashi was just slipping underneath his covers when Hiro made it back to the room. In his hands he had two glasses of milk with a donut resting on top of each.

"What are we watching?" Hiro asked, setting the food down on the nightstand next to Tadashi's bed. He stripped down to his boxers and crawled up next to his brother.

"I'm still watching that one paranormal one. You've seen a few of that, right? Do you mind that you've missed some?"

"That's fine." Hiro slipped beneath the covers. Tadashi's bed was larger than his, but it was still a tight fit for the two of them. The older brother propped the tablet up against his knees and wrapped an arm over Hiro's shoulders. Together, they munched on donuts and enjoyed the show together.

After the episode ended and Tadashi shifted to set the tablet aside, he realized Hiro had fallen asleep. With his head still resting on Tadashi's arm, he knew that he wouldn't be moving any time soon. Carefully setting the tablet down on the bedside table, Tadashi made himself comfortable and let himself drift to sleep.

Sometime later, Tadashi felt himself slowly wake. A noise and some movement had pulled him from his deep sleep. Groggily, he shifted and the movement stopped immediately. Alerted that something weird was going on, Tadashi quickly stilled himself and feigned sleep. After a moment or two the movement started again. Embarassment filled Tadashi as he soon realized that it was Hiro pleasuring himself.

Oh jeez, really? he thought wryly. He would have to have a talk with his brother about appropriate times to masturbate. Sleeping in your bro's bed was not the best time. However, he decided to save Hiro on a bit of embarassment now by letting him finish.

Even with his eyes closed, Tadashi could almost visualize what was happening right beside him. His bicep was still under Hiro's head, hand resting next to the teen's chest. Their sides were pressed up against one another so Tadashi could feel every small jerk and squirm. He heard every deep breath and shuddering exhale; the young man was a bit perturbed to realize that it was turning him on. That revelation made Tadashi move to stop his brother, but Hiro paused before he had a chance and Tadashi froze once again.

Tadashi thought maybe Hiro was finished. His suspision seemed to be confirmed when a warm hand gently grabbed his own and shifted so he was no longer pinned by the teen. However, instead of moving off the bed, Hiro carefuly placed his older brother's hand on his abdomen.

What the fuck? Tadashi tried to stay as still as possible. What was his brother doing? Within seconds, Hiro had continued to jerk off. The older brother thought frantically about what his options were: should he stop Hiro here? Let him continue and bring it up later? Or maybe just never mention it at all? His breathing hitched slightly as Hiro shifted upwards on the bed. Oh Dear Lord. Tadashi could feel what seemed to be the start of hair beneath his fingertips.

Hiro's breathing became more labored and he started thrusting his hips slightly. Tadashi's fingers moved up and down from that motion, gently brushing against the base of his brother's shaft as he jerked off. The young man cursed himself for being turned on by the obscene actions of his little brother. He's just a kid. He doesn't think about the consequences of his actions, he tried to rationalize.

Tadashi felt a bit of relief when Hiro climaxed. It probably hadn't been more than two minutes since he had woken up, but it felt like an eternity trying to remain still. He could feel his brother's heaving breaths under his hand. After a moment of resting, the teen slowly slid away and out of bed.

The older brother waited a while until he was sure he could hear Hiro's soft snores on the other side of the room before rolling onto his side. His mind was racing. What to do? What to do? Was this something that other people have had to deal with? If they did, were they aroused as he was? If Hiro was disturbed for doing something like that, was Tadashi disturbed by enjoying it?

With a sigh he forced his eyes closed, but sleep did not come easy to the troubled young man.

When Tadashi's alarm went off in the morning, he sighed heavily. He was already awake. The day's schedule seemed to loom behind his eyelids. There were 2 classes for today, not to mention his usual lab time in the evening. With a dejected sigh, Tadashi got up and got ready for the day, making as little noise as possible so he wouldn't disturb Hiro's sleep.

Throughout the course of the day, the young man contemplated how he would deal with Hiro. He tried not to let the subject distract him too much from school, but it seem inevitable. Half the time he was thinking about how he could possibly casually bring it up with Hiro that night and the other half of the time he was fantasizing about taking it further. Those thoughts surprised him; He was the protective older brother. His mind shouldn't even be thinking that, let alone giving it time to flesh out a complete fantasy of Hiro sneaking into his bed at night, touching him and begging for Tadashi to do the same...

With a start, Tadashi realized Honey Lemon was staring at him. Oh shit. Did she ask me a question? He let out a nervous chuckle. "Sorry...got a lot on my mind." Luckily his behavior didn't seem too far off from normal because the blonde accepted that and continued explaining her experiment.

When Tadashi returned home that night, Hiro was playing games on his computer. Of course, Tadashi thought with an eyeroll. He supposed it was better than bot fighting at least.

"Hey, what's up?" Tadashi peered over his brother's shoulder to see the new game he was playing.

"Not now, I'm winning." Hiro stared at the screen with grim determination that made a smile tug at Tadashi's lips. The gameplay on the screen distracted him for a few moments. A glance to the side at Hiro reminded Tadashi of the talk he would have to have.

"Listen, Hiro..." Tadashi took off his hat and scratched at his scalp, but before he could continue, the teen let out a triumphant yell and burst from his seat.

"Fuck yeah!"

"Watch your language!" Tadashi instantly reprimanded him.

"Sorry, it was just...that was so awesome!" Hiro grinned up at his brother with a sincere sort of delight that melted Tadashi's heart. The younger brother went on explaining in great detail the game mechanics, objectives and strategies. Tadashi laughed and sat on the edge of Hiro's bed, watching him walk back and forth with arms waving as he animatedly talked about his new hobby. Definitely better than bot fights, Tadashi decided. The topic he had wanted to bring up suddenly didn't seem like such a big deal. Maybe Hiro hadn't meant it the way Tadashi thought. It was probably just a one time thing, never to happen again.

"Okay, bro, you enjoy that game of yours." Tadashi grinned and shook his head before getting ready for bed. Hopefully everything would just be forgotten and Tadashi would never have to worry about it again.

Except Tadashi could not forget about it. Over the next few weeks, he watched Hiro like a hawk, waiting for some sign that the teen was either going to do something else or maybe fess up to doing it in the first place. Hiro seemed normal as ever, however, splitting his time between video games and tinkering around in the garage. At first, it was good news for Tadashi, but he soon realized that there was a part of him that was hoping something would happen. Late at night while Hiro was asleep and Tadashi lay in his own bed, his thoughts would wander, focusing on his brother's seemingly hidden perverted side. Each time his fantasies grew slightly more detailed before Tadashi would silently curse himself and force himself to think about other things.

"Hey."

Tadashi looked up from his tablet, still smiling from the message he'd read. Hiro was standing in his pajama bottoms outside Tadashi's area. "What's up?"

"Were you planning on watching a show tonight? Maybe I could join you?" Hiro pointed at the bed, as though his brother needed clarification.

"Oh." Tadashi hesitated momentarily before scooting to one side. "Sure. Hop on."

Hiro gave a toothy grin and jumped onto the bed. Without a pause, he slipped beneath the bedding and snuggled up beside his brother. "Same show?"

"Uh...yeah." Tadashi was feeling a little apprehensive. Was Hiro going to do something pervy? Did Tadashi want Hiro to do something? No. No. Of course not. He brushed aside that thought quickly. He settled down to watch the show with his little brother.

When the show ended, Tadashi wasn't surprised to see that his brother had fallen asleep first again. This time, however, the young man wasn't quite as eager to follow him into dream land. Tadashi lay awake, staring up into the dark. His heart was beating furiously. Was Hiro really asleep? Or was he pretending? Over the past few weeks Tadashi had found himself questioning the motive behind every one of Hiro's comments or actions.

Just as he was beginning to calm down and drift off, a movement brought Tadashi back to full awareness. Hiro had moved. Was he just moving? Shut up, stop being so paranoid, the young man mentally reprimanded himself.

"Tadashi?" Hiro's voice almost just a breath of air. Tadashi tried not to freeze as was his initial reaction. Play it cool, calm down... "Tadashi?" Slightly louder. Again, Tadashi said nothing.

For a moment, everything was still. Tadashi could clearly hear the sound of the freezer in the garage below due to the silence of the room. Clothing began to rustle, and then began the familiar movement that Tadashi knew as his brother pleasuring himself.

Holy shit, he's actually doing it. Tadashi tried to think of reasons why his brother felt the need to jerk of when they were in bed together. Perhaps it was just a turn on, and he did it for the thrill of being caught. Holding back a smirk, Tadashi thought, well, if he wants to fear being caught... With particular effort to remain as genuine as possible, Tadashi let out a small sigh and turned onto his side, letting his arm flop across his brother's chest. Hiro instantly stopped moving, his breath shaky and heart pounding away.

"T-Tadashi?" Hiro whispered, his voice even more breathy than before. Tadashi didn't respond. The two remained as still as possible.

When Hiro began stroking himself again, he did so in slow, deliberate movements. Tadashi quickly realized an unintentional side affect from changing his position: His groin was pressed up against Hiro's hip. It wasn't so close that it was uncomfortable but...every jerk of Hiro's body gave a tiny bit of friction to his own dick. It seemed inevitible that he would be aroused by Hiro's pervy actions. Don't try to blame this all on Hiro...you're enjoying this as much as he is.

Tadashi's breathing hitched slightly when Hiro shifted his leg and - quite deliberately - pressed his hip tighter against his crotch. It was probably very apparent now that he had an erection. And then, as carefully as he could, Hiro shifted.

Fucking hell. Tadashi bit back a moan. Hiro had moved onto his side, their erections now lining up. He could feel his brother's hot breath on his chest as he started rocking back and forth very carefully, creating a sweet friction between their two bodies. Tadashi was probably unnaturally still due to his effort not to move, but Hiro didn't seem to notice.

Sweaty fingers touched Tadashi's ribs. Hiro held onto him, his movements getting faster and more forceful. The older brother let out a soft moan, which caused only a slight pause in the rocking motion.

Despite his efforts to control himself, Tadashi pushed his hips forward, meeting Hiro half way. The teen gasped softly, his fingers tightening on Tadashi's side. He buried his face into his brother's chest.

Tadashi tightened his arm around Hiro and quickened his pace. There was no way Hiro could think that he was still asleep, but he didn't care at that point.

The two brothers rocked together, Hiro's bare erection rubbing against the cloth covering Tadashi's. Both were covered in sweat and moaning, whimpering, gasping together. Their movements were jerky and hurried as though they were both rushing to climax, but just the friction was not enough.

With a noise of frustration, Tadashi released his brother and rolled onto his back. In one swift motion, he pushed his pajamas down a bit and began stroking his erection.

Catching on to what his brother was doing, Hiro hastily followed suit. Neither spoke as they both stroked themselves to climax, Tadashi silent with a shudder, his legs twitching from the force of the orgasm, and Hiro letting out subdued gasps with each pulse.

The tension left Tadashi's body, and he was left feeling slightly weak. He could hear and feel Hiro gasping for breath beside him. As they cooled off in the aftermath of their experience, they didn't say anything. At first, Tadashi wasn't sure what he wanted to say, but when he finally turned his head, he realized that Hiro had already fallen back asleep. The older brother smiled softly and pulled the blankets over their bodies before letting himself drift off as well.

A/N: Well I thought it was just going to be a one shot but maybe I'll add another one later.