if you mean in canon it was genuinely the moment that it was revealed they were related, it all clicked and i shipped choita. i mean look at the way choso rushes in to defend yuuji from kenny. its giving big bro defending little bro from their drunk father-mother (lol) and im ngl i could wax poetic about canon choita and what they mean to me. BUT IF YOU GENUINELY, REALLY WANT TO KNOW WHY MY STUPID LITTLE BRAIN GOT INTO CHOITA, its because i LOVED choso at first sight and yuuji is the only one who has any canon chemistry with him (imo) (like i said i can talk all day about them)