One Thousand Times Before - The question that is....

I recently installed domain mapping on my multi-site. I have the root (and setup without the www)

I am using sub-directories for added sites.

How can I add the domain that a customer chooses without having them (the customer) edit domain records?

If I can't, what do I need to edit?

I have Cpanel on a Bluehost account and a dedicated IP address.

Please give me an example as the descriptions of others issues on the forum are hard to read; and I'm not even sure if they are addressing the same concerns.