Bolin's not sure how it happened, exactly. Maybe he crawled into his brother's bed one time too many after the many nightmares. Maybe it was Mako's constant reassurance - maybe it was simply just Mako's presence. Mako was the only thing he could rely on, in this world. He knew, knew, without a doubt, that Mako would be there in the morning when he woke up. That Mako would soothe him, help him relax after a particularly bad nightmare. That Mako wouldn't go anywhere, not like their parents.
For the longest time, watching Mako leave hurt. Even with their parents' scarf wrapped safely around his neck, he would cry. He used to beg that Mako never leave, that he not go to work. That he take Bolin with him. With time, Mako managed to calm him down. To convince him that he would come back.
And Mako did always come back.
That used to be enough. Watching his older brother come home, sometimes sweaty, sometimes dirty, but always tired, used to calm his frayed nerves. But then just knowing Mako was home wasn't enough. As Bolin got older, he had to hug his brother. Make sure he was real, that he was okay. Mako welcomed the hugs. He seemed to depend on them for comfort just as much as Bolin did.
Then Bolin started having nightmares about Amon. These were worse than the nightmares of his childhood. He could feel his bending slowly leave his body as Amon's hands lightly touched his forehead. In his dreams, he couldn't move. He couldn't scream. He just sat there, at Amon's mercy. Waking up and bending a rock across the room was never enough reassurance that he was okay. That he was safe.
He crawled into Mako's bed, like he used to do when they were children. Mako would sleepily drape an arm over his brother's waist, murmuring something about Bolin being safe now. That he was there; he would protect his brother. The first few times, this was enough. Bolin could close his eyes, feeling safe, and fall back asleep.
Then he started dreaming about Korra's bending being taken away in front of him. Or Mako's. And then his own - and he was always too powerless to stop it. He'd curl up along Mako's lean frame, tears streaming down his face, never making a sound. Mako would hold him; would try to reassure him. But it wasn't enough.
It wasn't enough until Mako lightly grabbed his chin, forcing Bolin to look him in the eye. "I'm not going anywhere, Bo. You know that," he whispered, brushing a tear away with his thumb. Slowly, Mako pressed forward, his lips lightly touching Bolin's. Bolin closed his eyes, the tears stopping as they slowly deepened the kiss.
When they broke apart, Bolin could feel an unfamiliar pressure on his thigh. His own pair of boxers felt tighter than usual. Blushing, he turned away from his brother, muttering an apology. Mako's arm remained around him, his fingers lightly touching Bolin's stomach.
"It's okay, Bolin," he said, kissing the back of Bolin's shoulders. Mako's hand dipped lower, fingers skirting underneath the waist of Bolin's shorts. "I think you need this." His lips moved up the back of Bolin's neck, leaving feathery touches as his fingers wrapped around Bolin's erection.
Bolin arched his back, pressing himself against Mako's front. Mako propped himself up on one arm, nipping at Bolin's neck as he began to slide his hand along Bolin's erection. Moaning, Bolin rolled onto his back, rubbing his hand against Mako's hardness through his shorts. His brother did so much for him. It wouldn't be fair if he didn't try to give Mako anything back - but Mako pushed his hands away.
Bolin realized it was only so he could take off his shorts, as well as Bolin's. Mako crawled on top of his brother, their erections pressing against one another. He wrapped his hand around both of them, the friction forcing another moan past Bolin's lips. As Mako's hand sped up, Bolin rolled his hips upwards, pressing further against his brother.
It seemed to last forever, but it was only a matter of minutes before Bolin reached the edge, gasping Mako's name as he came all over his brother's hand and stomach. Mako moaned in return, only needing a few more pumps before reaching the edge, himself. Panting, Mako collapsed next to Bolin, hastily wiping them both up with one pair of the discarded shorts before settling in beside his brother, his arm lazily wrapped around Bolin's middle once again.
"Feel better, Bo?" he asked into Bolin's shoulder.
Bolin nodded, closing his eyes. He hoped he'd be able to sleep peacefully, after all of that.