It's such a pedestrian gesture that it surprises a laugh out of Sora - not at all mocking, just really pleased with meeting someone unlike anyone else before. It's the novelty, as crass as it is! "Fair enough!" If this person's species is important, Sora will figure it out later. Really! He likes to be up to date on his new friends on these sorts of things.

Sora's gotten the memo about the whistling, so he'll shoo 'em off it they get to a point in the conversation where his new friend can't hear him. It's just nice to know that people are enjoying themselves, and it's not like anyone's really trying to get to sleep here anyway. Still... He points up at them. "Are they bothering you? I can try and put them somewhere else." How? Not really sure yet! He's willing to give it a shot if necessary, though!