How about a Fushimi + strain power scenario since those are fun! he gets hit by a strain that makes him flirty with everyone he runs into. Reactions from s4 + hmr?
Hilarity ensues, probably. Say Fushimi’s chasing the Strain with some of the alphabet boys when he gets hit with its power. Everyone’s worried and Akiyama crouches down next to him to see if he’s all right and suddenly Fushimi’s smiling sensually and leaning really close next to him and whispering in his ear while Akiyama stutters and tries to figure out what the heck is happening. The funny part would be if the power doesn’t just make him like casually flirty it makes him whatever Fushimi’s idea of flirting would be, so what he ends up whispering in sultry tones is something like “You know, I hate you the least out of all my subordinates.” And that’s how he is with all of them, like he tells Hidaka “Sometimes I almost kind of like you” and even to Doumyoji he’s like “Every now and then I find your stupid brainless smile endearing.” If he wasn’t climbing all over them and getting a little handsy no one would realize he was being flirty at all. Taking him back to headquarters is an adventure because he keeps casually leaning against each of them in turn and giving romantic one liners like “You’re really not as stupid as I thought you would be.” (That Fushimi, such a sweet talker.) Once they get him back, as soon as he’s sees Munakata Fushimi’s all right up next to him and holding his hands while telling Munakata how Fushimi totally looks up to him when he doesn’t feel like punching him. The alphabet squad is frantically trying to explain while Munakata’s just curious why Fushimi is being so honest and friendly all of a sudden, because in Munakata-land getting all up in someone’s personal space is just how you communicate friendliness and a sincere interest in another person’s well being. That Fushimi is flirting with him never crosses his mind, everyone decides it’s probably best not to tell him.
Later Fushimi escapes HQ and runs into Yata, of course, and is immediately super clingy, purring into Yata’s ear how much he missed Yata and how Yata almost doesn’t look like a total hoodlum virgin today. Yata is torn between being confused that Fushimi’s suddenly so friendly and freaking out because did you just bite my earlobe what the fuck. But after that bit of clinging Fushimi starts acting almost the same as he used to when they were friends, just maybe touching Yata a little more often than usual, playing with Yata’s fingers and running hands through Yata’s hair, the whole thing, and Yata starts to feel a little more at ease even though he’s still way confused. Eventually S4 comes to pick Fushimi up and on the one hand Yata’s now less confused about Fushimi’s behavior but on the other he can’t help but notice how much the way Fushimi talked with him and relaxed with him echoes the way Fushimi was when they were friends and if this is Fushimi’s idea of flirting was there something Yata was missing before.