I include a bit of background of my personal experience with the person I am referring to let the customer know there is more sincerity than just a person that I have a business card for. I also explain the customer's needs to the referral so there is a bit of understanding of the nature of the referral. This is all spelled out in the three way email. However, before this triangle connection happens, I reach out to the referral to make sure they understand the need and can accomodate the client.