[ It's hard for him to understand these sort of things, really. It's easy to see that something is bothering her, but even from her words it's hard to make up just what it is. The fact that he calls her by her last name, apparently, but what's so strange about that? He never called Takano by his first name either, and Kaito is.. well, Kaito. He can't imagine it any other way, even now they're both with the Church.

Does it even change anything about them, whether he calls her Tsushima or Kiraki..? ]

Kaito's different. I've known him since forever. [ Although the fact that Kaito got delusional and became a hikikomori after the whole deal with Haruto certainly cemented the fact that Mamoru could only call him by his first name even further. It was almost a little like he was looking after him, it'd just be weird to switch to calling him Yuuri at any given time then. He doesn't mention that part out loud though, since it's even an awkward topic now Kaito has gotten a lot better about things. ]

I mean..

[ He stops for a moment, letting out a small almost sigh-like noise. Not since he's bothered by what she's saying, but more just that he's bothered at himself. He wants to make her feel better, but he doesn't know how, and he doesn't know what to say - it's the opposite of last time, when what got him annoyed was the fact that she didn't know what to say, or rather didn't want to say anything. ]

.. why does it bother you when I call you like that, Tsushima? [ He doesn't even realise he's doing it again - Mamoru's just a little oblivious like that at times. But his concern is very much genuine, at least. ]