It's not a matter of "testing" it. It's just not an issue. [To Shun, this kind of thing is a minor concern. Definitely a concern, yes, but not on the level that he'd actually lose sleep or linger too much on it besides the quieter times when he doesn't really have anything else to think about.

Since he already established that he doesn't think it's a problem, he leaves that, but as for the changing unexpectedly, he shakes his head a bit.] Chances are there won't be warning signs. When I change like I said I can do earlier, I do it suddenly. Your best response would be to have people prepared to come snap me out of it. Preferably violently, because I don't listen to much else in that state unless I have to. [Which generally entails punching him out and then talking when he's slightly calmer anyway.

While Fubuki might be trying to annoy him with the pillows, Shun still isn't actually bothered by it. He is, however, not exactly going to play along - rather than catch it and throw it back, he lifts his leg and spin-kicks the pillow back at Fubuki much faster and harder than a playful throw would have produced.]

Then that's your bad idea. [His tone is a little dry there, so he's...probably deriving some humour out of this, somehow.]