teenage chuuya and dazai who accidentally developed quite a couple of inside jokes over the course of their partnership, and one day just have the most horrid case of giggles while on a mission.
the setting is all intense and they’re doing what double black usually does—dazai being the brains and chuuya mainly being the one kicking ass. but then something happens that triggers one of chuuya and dazai’s inside jokes in dazai’s mind and he slowly starts to lose it.
he whispers it to chuuya as they’re setting up their trap, who at first hisses at him to shut up and focus up, but then the joke processes in his mind and he involuntarily starts to smile and tremble.
dazai brings up the joke again in combat as he knocks out one of the men he’s fighting, close to hysterics over it even though it’s probably one of the most unfunny and nonsensical jokes they have. he’s hunched over and his body is shaking, and another enemy uses his moment of vulnerability to go and strike him from behind. chuuya quickly takes the enemy out. he screams at dazai to focus up yet again.
but the louder dazai’s laughter gets, the harder it is for chuuya to suppress his own. his face slowly starts to turn red, not from the physical activity, but from how fucking stupid the joke is and how that’s exactly why chuuya is on the verge of going ballistic over it like dazai.
they’re both out of breath by the time they finish fighting, a couple of new scars littered on their skin, bruises already forming on their knees from the particularly gruelling mission, and dazai brings up the joke one final time in a hushed voice, covered in grime and blood and ick, chest heaving. and chuuya, who looks identical, practically shouts in laughter, sending them into a full blown fit that has them clutching their chests and stomachs. they stumble forward and backward and inhale sharply only to immediately burst out laughing again when they look at each others faces, which read the inside joke they’re both thinking. they don’t account the moment in their mission report, but hirotsu certainly does in his.
