More of pining!Yuu and maybe how Mika realizes the meaning of all of the hints he gives him?
Okay so, since Mika is the only person Yuu’s ever been in love with, he doesn’t really know how to express his feelings. He isn’t good at flirting even.
Heck, whenever he says one of those smooth lines to Mika, it’s because he actually means them, and he just doesn’t realize how romantic he sounds.
It’s only later, when Shinoa teases him about it, that he realizes just how obviously infatuated he might have sounded.
Shinoa: *dramatically* stay alive… for me
Yuu: *blushing furiously* SH-SHUT UP!
Funnily enough, Mika doesn’t realize Yuu’s feelings even when it’s so obvious to everyone, and that’s both a relief and a problem for Yuu.
Yuu is clueless about how to show Mika his feelings are romantic. If Mika hasn’t realized yet what with how Yuu constantly and unknowingly expresses them, he won’t realize it when Yuu purposely shows them either.
Honestly, Mika is too preoccupied trying to keep Yuu alive to think about Yuu’s weird but cute attempts at wooing him.
About the way Mika finds out… it’s hard to imagine him realizing, to be honest. On the opposite situation, Yuu could realize Mika’s feelings with help from other people or by himself, but in Mika’s case, with his low self esteem and stuff, even if he was directly told that Yuu loves him he would probably doubt it. The only way he can find out is by Yuu confessing his feelings, but I think that even then it would take a while for him to process it.
Yuu: I love you!!
Mika: *startled* oh, umm… I love you too, Yuu-chan
Yuu: y-you do?
Mika: yeah, you’re my only family
Yuu: no, Mika- that’s not actually what I meant. I meant I love you like uuh i-in a romantic way
Yuu: I- I’m in love with you! I’ve been for a while
Mika: but why?
Yuu: what do you mean why? You’re- you’re awesome, and strong! And beautiful, and smart, kind and sweet… You’re everything I could ever wish for and I- I want to spend the rest of my life with you
Mika: why would you want to waste your life like that?… You could be with whoever you wanted but you had to go and pick me, a vampire…
Yuu: we don’t choose who we love, Mika, but if we could… I would still choose you.
Oops, it became angsty and corny by its own will.