I have done daily coffee enemas for 10 months.
So I guess I’m some kind of expert 🙂
The fact that You feel the caffeine is because Your intestines have absorbed the coffee.
To avoid this You need to be hydrated.
I used to drink two big glasses of water first thing in the morning and then do the coffee enema.
Also important is to have empty bowels, so You can hold it for 15 minutes.