I used to get the jitters sometimes after a coffee enemabut I learned to insert the tube no more that three inches into the rectum. this really helped me. I also do it first thing early in the morning so if there is any unwanted stimulation from the caffeine, it's gone by the evening. (but there never is....) Also, I take some aloe vera after the enema for cleansing and soothing, unless I forget, which I did this morning (darn!!). I do the enema in order to cleanse and detox the liver. It might also be a good idea to do a water enema right after the coffee enema to flush out any leftover coffee still in there, I just read about this step a few moments ago.
So, I'll do this the next time. And also, only use organic coffee with a lot of caffeine. I get my coffee from sawilsons.com. This is a very good website and there is a lot of really good info!!
I hope you find this answer helpful.