Humour is... not the reaction he expected, not at all, and for a moment he pauses. He's... honestly concerned, for a fraction of a second, but Ned... Ned is so quick to reassure him. Maybe the words themselves aren't necessary, but he's nevertheless reassured.

And perhaps laughter is better than many reactions. That in itself is almost fascinating, something he wants to understand, one more thing about Ned he must learn and know.

With the encouragement, thought, that silent request for more, he can only comply, deepening his movement, though he's still slow, still careful.