Natsuno's hand goes through the other side from his small test, a hint for the answer Tidus gives with a shake of his head.

"We'll be fine." And mimicking Natsuno, he moves his hand out too, going through where the barrier had shone briefly. He takes a step forward, and his hand hits in front of where Natsuno's reached out. He can't cross Natsuno's barrier.

"It stops anything attacking your front. It covers you, but it's a weak spell. Fine for rats."

Nothing Tidus was worried about.