@Running7........It sounds like you had an open system colonic like a Libbe or Angel of Water system. I received my first colonic a couple years after I got married in my mid twenties. I'd been having migraines and constipation issues for years. My wife had been getting colonics every couple months before we even started dating. She finally convinced me to give it try, even paying for my first visit and setting me up an appointment with her therapist.
Her therapist at the time was an adorable young woman, a registered nurse named Angie. She used a closed system colon hydrotherapy machine called a Dotolo Toxygen. With a closed system, the therapist inserts a 1" thick plastic proctoscope type nozzle, called a speculum, about 3-1/2 inches up the client's rectum. It looks intimidating at first glance, but IMO it really isn't that bad, even my first time having it done. To begin with, I changed into an exam gown with an opening in the back. She had me lie on a padded massage table on my left side with my right knee flexed. She opened up the back of my gown. Don't be embarrassed, she's seen hundreds of bare butts and anuses.....she is a nurse after all. She lubricated the speculum, then asked me to breath in and out a few times. She talked me through the process as she lifted my butt cheek and touched the speculum to my anus. One more deep breath in, the as I exhaled she slowly and gently slipped it right in. It's just felt kind of cold and uncomfortable for a few seconds, like getting a prostate exam the first time. But it wasn't painful in any way. After several minutes, and as you relax more, you become less aware there's a speculum inserted. Less something uncomfortable up there that fades to just a feeling of gentle pressure in your backside.
Once she got the waste hose and water inlet line connected. she held it in and assisted me in turning onto my back with my knees raised and feet resting on the treatment table. She even had a foam triangle to rest my knees on for comfort. She started a gentle trickle of warm water, nothing harsh or under high pressure. You almost can't feel it at first. Then after a couple minutes you start to notice a subtle warmth migrate through you lower belly and up your side as the water gradually fills higher up the colon. Then suddenly a sensation of really needing to poop it back it (peristalsis), I told her and she turned a knob on the machine, and the waste came out and down the hose and into the machine where you can see what's coming out under a lighted glass tube.
She also massaged my lower belly gently with coconut oil as I was being filled. This supposedly helps loosen the hardened stool in the gut and induce peristalsis. She repeated the fill and release process about 8 or 9 times, pulsing the waste hose with her left hand until not much more than cloudy water was coming back out. It took her about 45 minutes to clean me out. After the time was up, she had me turn back onto my side, held a napkin to the speculum and gently pulled it out of butt. I had to go sit on the toilet for about 10 minutes and poop out the rest of the water that doesn't go through the speculum. Then I got dressed and went home.
Other than feeling better, and lighter, I wouldn't have known I even had a colonic just an hour earlier. My butt wasn't sore or anything, considering having a speculum up there for 45 minutes. It all comes down to how gentle and competent your therapist is and how relaxed you are before a session. I've had dozens of colonics since that first visit.