Imagine being Fuutarou in that scene and having to be all like "damn, Itsuki, you fuckin' smart, all intelligent with your thick body and horrific same face. I would totally study with you, both my blond alter ego and the real me." when all he really wants to do is study and eat Raiha's food in his room. Like seriously imagine having to be Fuutarou and not only stand there while Itsuki flaunts her poor knowledge in front of you, the favorable lighting barely concealing her sweaty tits and big belly, and just sit there, test after test, hour after hour, while she perfected the Binomial theorem. Not only having to tolerate her monstrous fucking visage but her haughty attitude as all the sisters tells her she's STILL GOT IT and DAMN, ITSUKI STUDIES LIKE *THAT*?? because they're not the ones who have to sit there and watch her mannish fucking gremlin face contort into types of grimaces you didn't even know existed before that day. You've been studying nothing but a prolific series of famous writers like Dostoevsky and Chekhov for your ENTIRE SCHOOL YEAR coming straight out of the poorest district in Tokyo. You've never even seen anyone this fucking dumb before, and now you swear you can taste the sweat that's breaking out on her plump stomach as she sucks it in to writhe it suggestively at you, smugly assured that you are enjoying the opportunity to get paid to sit there and revel in her "statuesque (for that is what she calls herself)" knowledge, the knowledge she worked so hard for with personal previous tutors in the past years. And then their dad call and asks how they did in their tests, and you know you could whack every single sister in this room for being so dumb before the apartment security could put you down, but you stand there and endure, because you're fucking Fuutarou. You're not going to lose your well-paid job for this. Just bear it. Hide your face and bear it for Raiha's sake.