Bruh... just fuck already. You both clearly want to and both have expressed it to an extent to each other so all this pussyfooting around is just getting annoying.
This is a fairly extreme example of how romance narratives often rely on characters being utterly unwilling to communicate. Like a single, short, frank conversation would completely unravel the entire plot here.
Naoto: "Luna, be honest, how do you feel about me?"
Luna: "I've wanted to date and have sex with you for a long time."
Naoto: "I feel the same way."
And then there would be literally nothing else in the plot to resolve