There is something to be said about not rushing the intimate time spent together, the distractions that are provided by your SO are a welcome part of being taken care of.
Speaking for ourselves, we both seemed to do better by beginning at a very slow rate for the first enema of a day. I believe there is a natural tendency for the valve action at the juncture of the colon and rectum to prevent a reverse flow from the rectum back into the colon. There are sensory nerves in the walls of the rectum that detect when it is stretching from normal faces accumulation and that is the trigger mechanism that tells you to go to the toilet. It seems logical then that a pint of solution quickly introduced is going to be responsible for triggering a strong sensation to defecate, and also to prevent the enema from going up into the colon. Our method then was to slow the first pint of solution, maybe ten minutes for that, to avoid triggering that reflex, after that you could quickly introduce the next quart or more and it easily moved higher into the colon.
Subsequent enemas were easy at high flow rates from the start and were easily tolerated for the rest of that day or maybe even out 24 hours.
Still have to go back to the first observation, why rush an intimate time, there are lots of possibilities.
If intimacy's are not a factor like with illness or what ever then let the need establish the speed. The aspect that I like more than anything is for there to at all times be more solution so every few minutes another 25ml is given. We normally had two bags filled, maybe not fully, for the act of finishing one and another one starting seemed more enjoyable.
There are lots of comments about the techniques to achieve a slow flow rate, foremost on our minds was not allowing the reverse flow which is difficult from cramps and more so from an orgasm. The newer equipment is often fitted with a check valve that prevents that, this opens a new method to introduce the enema to your SO, that is to open the clamps fully and just pick up the bag for a few seconds or more and lay it back down for a pause.