The volume issue is probably a correct one. I've graduated from taking four to five to six quart enemas. And usually have no problems.
Ten years ago (I was much thinner) and took 8 quart enemas on several occasions, very slowly over time. I DON'T recommend it. But I did it then.
An 8 quart enema is about 16 pounds, like a very large baby. And to get it in I went slow and with Lamaze like cleansing breaths.
With eight quarts of water in me, there was not room for much else, including air.
I could not hold it long.
And I often got headaches afterward, which I presume was due to water intoxication.
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Large volume enemas and thinness versus fatness.
Years ago, I read that at hot dog eating contests, thin hot dog eaters had an advantage: there abdomens were mostly muscle, which is protein, which stretches easily. Protein is very stretchy. Fatter persons have a ring of fat, which does not stretch and acts like a girdle, thus allows less space inside.
I am certain this is also true for large volume enemas.
Also, there is a vitamin guy, Gerry Hickey, Invite Health, on WOR Radio NYC (Saturday or Sunday mornings) who claims he has seen autopsies of fat people, where the fat is inter-woven in the muscles of the stomach. (Think of marbled beef.) The fat again resists stretching. (And also leads to cancers. A good reason to lose weight.)
Thus a thinner person may be able to stretch more to accommodate a large volume enema, where a fatter person will not.
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Back when I was taking 8 quart enemas, I was 180 to 200 pounds. And my stomach did stretch to accommodate the large volume enema, given slowly over about 15 minutes. (This was physically stressful, so I don't recommend it. Also it didn't really add any benefits: it wasn't any more flushing, cleansing or sexier than a 6 quart enema. It was mostly just the brash arrogance of taking an 8 quart enema.)
I am now about 240 pounds and simply can not accommodate an enema much more than 6 1/2 to maybe 7 quarts. Most times I can just let a 6 quart enema just flow into me, especially after I've taken a cleansing enema of maybe 5 quarts.
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