Responses
He had once made the comment that with a 20 year age gap, he was old enough to be his father. And no, if they did anything at that time, when Yuuya was only 6, it would not have been incest, as there's no familial relationship between them. But it would have been pedophilia, and Azuma would probably have shot off Nishinomiya's dick.
On page 190 ryuu seriously looks like yuuya's dad. It would.be considered incest then, well if they did it then.