trying to record affi custom field to display

I am using s2member and affiliate pro plugin… what I want to achieve is to create a custom field for a user to enter the value when editing their profile to be called and displayed to their refferals.

Now I have done the custom field using s2member and have named the field en_username. Now this field is not required on registration, it is to be filled in afterwords in the profile. This code [s2Get user_field="en_username" /] pulls that field entry to the user of the user, but I want it to pull from one level up….

However, I want to know how I can carry this fields entry over to be displayed to the referral of that affiliate.

so affiliate number 1 joins my platform under me, in their profile they are required to update an empty field called en_username, they have to click a link with my en_username(jamesiscool) being called in and displayed, then they create their own and so they do with (johnsmoneyman)… now affiliate number one has somebody join him and the new affiliate now has to fill in his empty field called en_username, so he clicks a link which has pulled in Johns en_username(johnsmoneyman)…. and this repeats…

Does this makes sense.

Struggling to explain this but hope somebody can understand and help.

Many thanks :)