This topic makes me re-live the details of those enemas mom gave me as a child as a result of going 4 or 5 days without a BM.
That Wards combination syringe would come out of the bathroom closet and the other enema necessities would be assembled, box of Ivory flakes, pitcher for mixing the soapy enema solution, vaseline.
The enema position was laying on my side on the floor on a towel, left side, left leg drawn up. Almost as soon as the enema was started, there was a sensation of pressure. After only a few ounces I would be complaining to mom, "Mom, I'm full already." She would almost sternly reply, "Oh, hush! I havent hardly given you any yet."
Of course, this situation was created by that thick, long chunk of constipated poop that initially blocked the enema from going up into the colon leaving only the rectum available to receive the soapy liquid.
The shut-off clamp would remain open. I would continue to complain. Mom would continue to encourage me to endure the initial fullness and that "the pressure will go down in a second, honey."
Finally there was a little flutter in my tummy. The pressure immediately dropped. Mom's enema had finally breached the blocade, stretched the bowel wall 'til it could flow around the "plug." I could feel the surge of the enema around the impacted poop as it flowed up into my colon comfortably.
The expulsion details are just as memorable. After the required retention and the onset of those enema induced bowel contractions, I was allowed onto the toilet. A little of the warm soapy enema started coming out but stopped as the huge, thick poop was pushed down and sealed the "outlet." I could feel the enema working, trying to be expelled, and I could feel the big round cylinder of poop stretching my sphincter. Finally enlarged, the mass zipped out of me like a long poop torpedo and splashed into the toilet sending cold water from the bowl up against my bare bottom. This was followed by the contrasting warm enema expulsion along with those smaller round things that my mom and I referred to as "tumble turds."