#rijyu

breakfast:

rio and ichiro become fast friends and workout buddies after getting to know each other a bit better, and go on early morning runs together samatoki and jyuto get to sleep in a little longer, but are always up to greet them with coffee and sleepy kisses when they get back the four of them cook together and have breakfast around the fire pit out in the yard (ichiro has been gently teaching rio what is and isn't an ingredient)

lunch:

when jyuto's working a big case and/or samatoki's dealing with major katen-gumi issues, they sometimes have to leave home super early or don't even have time to sleep at home the night before so ichiro and rio bring their bentos to their offices on those days, and samatoki and jyuto always take the time to snap a picture of their food and text it to each other like "my aisai bento is better than yours" "your aisai bento has a lizard in it dumbass" one day ichiro and rio are also in a hurry and after cooking they each grab the wrong bento and samatoki ends up with the one with [redacted] in it but still eats it all because he thinks ichiro made it (but i mean he loves his bros so he would also eat it even if he knew rio made it)

dinner:

i can see them having a regularly scheduled double date, like a proper double date out at a nice restaurant and all, once every two weeks or something like that (though sometimes it feels date-y, sometimes they just feel like a friend group out for food) after a few drinks, samatoki and jyuto maybe both get a lot more tactile and even competitive about how many kisses and cuddles they can get in a semi-public place (answer: a lot of kisses and cuddles, their boyfriends are so doting lol)

that's all for specifically uhh i'll call it house!verse or something (i just have big big big mtc+bb found family feels in general)

as for more general birdgun + icsm hcs...

not exactly a double date but i will always love the mental image of samatoki and jyuto getting into an argument and ichiro and rio just each picking one of them up and physically carrying them away to let them cool their heads

(even funnier version: samatoki and jyuto get into one of those cartoonish fights where they just become a cloud of dust and smoke with a limb occasionally popping out, ichiro and rio dive in to each grab one of them and come out with the wrong one lol)

also hc when samatoki brings ichiro out with him and rijyu for the first time and is like "yeah so... we're dating now" i can see jyuto just giving them a scathing look like "really? you can do better" and samatoki being like "HEY?! ICHIRO IS AWESOME" and jyuto just hits him with an "i know. i was talking to him."

and, last but certainly not least, beach date! obsessed with the idea of them all going on a beach trip together (though realistically that would probably be less of a double date and more of a family outing because of course they would take jiro saburo and nemu too)

but like getting a little too competitive over beach volleyball is of course a must lol

then later ichiro and rio each bringing over a big thing of shaved ice to share with their partner (samatoki and jyuto getting a little too competitive about that too, racing to see which team finishes first, all of them lying on the sand moaning about brain freeze when the younger siblings come over to be like wtf are those nerds doing)

team effort to bury rio in the sand while he takes a nap (he is the sand guardian guardian of the sand)

also sand sculpture competition where ichiro gets really pumped about the idea of making a miku and samatoki has to patiently explain to him "ichi you are having creation ideas above my skill level" and they end up making like a rough imitation of ichiro's speakers or something instead then turn around and find that rio and jyuto have made a neo armstrong cyclone jet armstrong cannon structurally sound military bunker somehow

and taking a boat out for some scuba diving! all sorts of docile sea creatures coming up to actual disney princess rio to say hello, jyuto staying a wary distance away but filming everything with a gopro, samatoki and ichiro keeping a closer eye on things to make sure rio doesn't mistake his new docile sea creature friends for food