bond stats question

SosaRey

Ok, I just got gin's 2nd stat in bond, which is with ikkaku.  Now my question,do I have to put ikkaku in formation to receive the bonus stat?  Or do I have to put him in aid to get the bonus stat?

I put him in aid and my by slightly increased, but when I put him in formation I notice that on gin's tab I can upgrade the skill.

So, does the partner have to go on formation, or aid, to receive the skill upgrade in bond?