[it would be impossible to miss the blatant transformation of emotions on Kaworu's face as his smile lessens, and for a moment, Nageki considers immediately forgetting his uncertainty and doing as Kaworu suggested, sure that he must have done something wrong. he thinks better of it a second later, however; Kaworu clearly wants him to enjoy this, rather than doing it out of a poor sense of obligation to him, and Nageki is hardly confident in his ability to pretend. it isn't that he doesn't enjoy the piano, it's just...

maybe it isn't for him, and maybe Kaworu can tell. is that really all that's bothering him, though? there's something else in his pause, and the mask on his face, that reminds Nageki a little too much of Kaworu's younger counterpart. there's definitely something else that Kaworu isn't telling him, and it's for no reason other than pure worry for his friend that Nageki finds himself wanting to know what it is.

after a small pause on his end of the conversation, Nageki tries his best to speak up.]

There's something else bothering you, Kaworu. Isn't there?

[is that too confrontational? trying to ease the possibility, he adds in a quieter tone,]

If you don't want to discuss it, that's fine. I'm just... concerned.