"I mean, if I'm already not comfortable with you watching me, I don't know how I'm going to get comfortable about the idea of dancing together with someone."

Because he trusts Tidus, no matter how many dumb antics they get up to. And he is comfortable with him, yet he still doesn't even dare to dance knowing that the other is here watching. He's pretty sure he'd feel similarly about it with Taiki, even though he also trusts him with his whole heart. And watching is still a step down on the embarrassment ladder compared to dancing together!

It's already visible on Inigo's face. Just how much he dreads the very thought of it. Like he's getting shy over a mere hypothetical.

"I think I've still got a long way to go before I could do something like that."