i think this is one of those moments — similar to when they travel to germany — where ciel is trying to understand sebastian. he doesn’t give him a hostile look for calling him a child; instead, it’s a contemplative one, focused on the way he phrased the sentence. it can also be translated as “children need sleep to grow up healthy.”
ciel doesn’t know whether sebastian is mocking him, or genuinely caring in a way that forgets there is no future in which ciel gets to grow up. the contract, which for sebastian was meant to last only a fleeting moment, stretches on longer and longer — but ciel is fully aware that its end is closer than its beginning.
sebastian, meanwhile, seems to think more and more often — perhaps unconsciously — about a future for the two of them, a future that simply does not exist in ciel’s mind.
it’s one of those examples that suggests sebastian may be slowly drifting away from the idea of devouring ciel, even if he himself hasn’t realized it yet.
