There were just a few things Bokuto Koutarou was scared of: Yukie and Akaashi when they got angry, those "tiny spiders with extra-long legs", and even the Michelin man.
But Bokuto also had fears that genuinely terrified him, that made him freeze and tremble, that made him go silent. What he was most scared of was thunderstorms.

Whenever there was one, he'd close himself somewhere, shutting his eyes tight, trying to muffle the noise with his hand on his ears, and wait until it's over.
For how shameless Bokuto was to show his feelings - or even overreact over many things - this embarrassed him.
He felt pathetic. When he used to go into his emo mode, he somehow pulled himself out of it.
But during thunderstorms he was helpless.

That was why Koutarou's mood shifted from being happy for going on a vacation to the beach for the first time with his boyfriend to being anxious when someone told him about the oncoming thunderstorm.
Usually Koutarou went straight to the point and told when something was bothering him, but Yaku was quite excited, despite the beach not being his favorite place, he could afford to rent a little house and he loved the location.
So he kept his mouth shut.

When the thunderstorm came, Yaku complained about not being able to go outside for that day.
Then he noticed how distressed Bokuto looked and all his attention went to him.
He asked what was happening, and got even more concerned when Koutarou avoided making eye contact.

The first thunderbolt made both of them flinch, Yaku cursed under his breath saying how he didn't expect that.
When he looked back at Bokuto, he was surprised to see him shutting his eyes and quickly bringing his hands to his ears, trying to prepare himself for the loud thunder. He ended up getting scared anyway and he started trembling.

No verbal explanation was needed, Yaku took Bokuto's hand and guided him towards the bedroom.
He made him lay down then he wrapped his arms around him, hoping this would comfort him a little.
His shivering lessened, and he slowly put his arm around Morisuke's waist, burying his head into the crook of his neck.

Koutarou felt his own heartbeat calm down. Yaku's embrace was warm, it was comforting. He felt protected, for the first time.
He usually was the one putting people at ease, he wasn't really used to that.
He'd flinch at every thunder, and he'd pull Yaku closer to him. When he realized he might hurt him, he started being more careful.
Morisuke noticed this, so he went for another way to make him relax.
He started playing with his hair, scratching his scalp, and rubbing soothing circles on his back.

It seemed to work, he let out a relieved sigh, and he planted multiple kisses on Bokuto's forehead.
Koutarou soon started drifting off, when he was sure he was asleep he pressed another kiss against his forehead.

Yaku began dozing off too not much later.
With a calm, soft, and serene expression on his face he fell asleep, content he could help Bokuto in some way.