I am not sure how you mean by the enema being more difficult.
I am far from an expert in these matters, but I have looked over several sources of information for enemas and have done many enemas myself.
I cannot say if and what I eat effects the enema itself. I think the general idea here is, does having stuff in your large intestine impact the ease of taking in and holding an enema. I do 1 or 2 water enemas
in the morning before my first coffee enema
of the day. I honestly feel it aids in both receiving and holding an enema. I could be mistaken, it could be imagined.
A lot of people fear and suspect that doing many enemas makes your bowels become dependent upon enemas for defecation. I imagine that when doing 5+ enemas a day, you have little matter in your large intestine. I find that eventually, I seem to stop defecating, my body seems to expect an enema. If you are doing just one or two a day, that may be different, but I don't know about doing only a few a day.
It is said that toxins and such are released into the coffee solution in your large intestine just below your liver. I've read that rinsing your large intestine after releasing the coffee enema
may be of some benefit as the toxins would not be re-absorbed. I use a garlic enema as a rinse for 3 out of 5 of the coffee enemas
each day. I do try to hold the garlic enema for a short period of time (3-6 minutes) to gain something more than just a rinse from the garlic. I never read anything suggesting anything other than just coffee enemas
(no pre or post enemas).
To give you a better illustration, the first set of enemas I do in the morning start with a water enema
or two, then a coffee enema, then a garlic enema.
I highly recommend getting a bidet if you don't already have one. Mine attached to the toilet beneath the seat, included everything for easy installation and it wasn't very expensive. It's worth the extra money to get a bidet that draws from both the warm and cold water. Spraying with warm water instead of cold is so much more comfortable. Mine has a nozzle rinsing feature that also acts as sort of a pre-water warmer so the initial sprays of water get up to temperature much more quickly. I almost feel comfortable with doing away with toilet paper and just using a towel to dry with. Consider how much you might wipe between each enema.