See what did I say, not a problem, she already knew, and here comes the teasing. Glad to see Takumi is really thinking about this and recognizes the issues that might arise, from the destruction of their relationship, to his desire to be seen as the adult man he is by the woman he loves.
And also I totally called it, though it wasn’t the sandwiching that was the trigger, definitely contributed though let’s be honest, but seeing her showering would most certainly awaken something in any man, especially for his age at the time. And ever since then she’s been the only one he’s had any feelings for.
I can’t help but wonder just how painful it must have been for those 10 years of being treated as nothing more than a kid, worse yet being seen as another one of her children, when all you want is for her to treat you like an adult, or see you as something more. And her saying that he should start calling her “mama” and that she sees him like a son definitely broke the dam holding his feelings back. After that he decided he wasn’t going to hold back anymore and just unload it all, whatever happens, happens. He knew the risks, but even still he made up his mind, gotta respect the level of determination it takes to go that far.