First off dark roasted and/or espresso coffee has less caffeine in it than light roast. You don't want to use any of the dark roast coffee's. You can use Organic light roast, preferably low acid shade grown. I recommend buying SA Wilsons www.sawilsons.com
Basically the coffee should be boiled for 5 min uncovered, then simmer covered for 15 min. Use only glass or stainless steel pot for boiling. (Do not use a coffee maker with a filter). Cool and strain with a fine stainless steel strainer. Coffee should be between 98-105 temperature. You can buy those digital thermometers for a couple of dollars at the store. Use Vit E or coconut oil for lubricant when giving the enema. More directions in the pages listed below. Read a lot of the information before doing the coffee enema so you will know what to expect.