The navel was as wide as a cave-entrance for Xix as he heard and saw some lint and a large scar covering the entrance of the navel, followed by a small hole leading straight to the abdominal cavity and other organs, it looks like he would have to squeeze in past the scar-tissue, muscles and belly-fat just to fit into the hole, which would be a tight squeeze indeed, but it appeared that it was the right size to squeeze in... The noise would be purely organic in nature though.