My experience with coffee enemas is that I always feel great after doing one, along with a lot of energy.
Do you do a "cleansing" enema or two just before doing the coffee retention enema? Are you using filtered water or pure water when doing enemas? Do you always use organic coffee?
Sometimes enemas are easier to do for me than other times, as far as how long I can wait before 'releasing'... Is that what you mean?