The process actually involved three separate enemas.
In the late summer of 1959, my parents noticed that my right shoulder blade was turning perpendicular (inward) from the rest of my torso. Idiopathic dorsal scoliosis was quickly diagnosed, and three months later, I entered Geisinger Medical Center (Danville, PA) to undergo the body-cast-and-spinal-fusion procedure commonly recommended at that time.
Applying the cast, (from the top of my head to just above my knees), took about an hour, during which I thought I was being baked alive. My first enema (a disposable) came a few days later, from a young male nurse who was as put off by the process as I was.
I'll always be able to tell you who won the '60 Rose Bowl (Washington over Wisconsin) and a couple of days later, I got another disposable, this time by a young woman who let the cat out of the bag and told me it was "for your operation tomorrow"; I hit the panic button until I was told "It's just to look at your back", and the trusting soul I still was at the time swallowed the story whole.
The next morning at 7, I found myself on the operating table, smarting from the intravenous anesthesia needle just put through my wrist, and silently vowing to go down fighting. My recovery was as fast and complete as could be expected, but three days later (a Sunday evening) two mature ladies came to my bedside and informed me that I was to get another enema -- but this one would be "the kind you'll get at home" -- Whaaaat?
The two ladies used a metal irrigating can instead of a disposable and informed me that the water would be more soothing - warm and soapy. I can't recall whether my own little "water works" (it wouldn't be used for anything but piddling for another four years) took any notice physically, but I felt very little pressure until one of them prodded my stomach and advised "better stop -- he's getting pretty full". I expelled and soon felt far better than I had in quite a while.
Both of the two ladies were called away for a few minutes, which gave me an opportunity to examine the device which had penetrated a very intimate part of my anatomy yet left me much more comfortable. I never needed an enema after I returned home, but in another year or so, I'd learned about enema bags from a mail-order catalog, and when I found one stored at home around the time my sexuality made itself known, decided to experiment on myself.