Well, start with water, and then, when you have some experience, you can start thinking about coffee or about anything else.
Any herb you add into water carries a risk, even risk being very small.
Do you drink coffee?
If you can tolerate coffee as a drink, odds are in your favor that you will be able to well tolerate coffee as enema.
Even in that case, use very small amount of coffee the first time you try it, to avoid any unpleasant surprises.
may be too much for some people.
To make sure coffee enema
is not too much of a shock , cleanse your liver with a few spoons of oil mixed with juice daily, so you don't experience too much of a reaction when you start with enema.