[ Leo's pretty sure the secret isn't the costumes, anyway. They're both idols. While Leo can't recall off the top of his head anything in the Eden or Eve lineup that was that showy with skin (he pays more attention to the music than anything else, anyway) it isn't like any of them are unfamiliar with throwing on whatever a show calls for.

Mostly he's thinking it's kind of a Ra*bits vibe. Nazu and his kids would totally fit in this kind of thing, wouldn't they?

So the secret is probably either Nami's expression or how close they're getting, but Leo figures the latter isn't a huge deal given Eve's whole theme, and adding the contextual knowledge that Hiyori can be pretty territorial.

Not like Leo has experienced it much since no one who has known him for even five minutes would take his actions towards Jun as anything other than excessively friendly - presumably anyone Hiyori didn't know half as well probably wouldn't be able to get away with saying "I love you" or texting Jun at weird hours or begging him for cooked snacks in so on without being on some kind of list, but none of that from Leo means much other than he likes the both of them in his usual open way. Actually, neither of them has responded in any surprise or confusion to his I Love Yous or late, so they're at the level of "oh the catchphrase" tolerance that Knights reached way back when.

He takes Hiyori showing something like that off to him as a measure of trust and friendship and beams back at him. ]

Nazu's kids fit this kinda vibe, don't they? Though it works pretty well on you guys too! You're the type who likes to tease your partner, huh?