Gallonist,
Just based on 50+ years of self-given enema experience, I've just never felt the urge to rinse ever, even after soap, saline, glycerine, lavender, peppermint or any other preparation. My belly, including this morning after 2 enemas yesterday of Bronner's peppermint soap (first peppermint ever) feels wonderful.
However, all this rinsing discussion does bring up an interesting concept. My anus/sphincter is extremely sensitive to irritation even after sometimes one benign enema of salt and/or mild Castile soap, each at 1sp/quart. My belly on the other hand could easily take multiple enemas a day and be happy, like this morning. I'm beginning to wonder if anything but pure saline 1 tsp/quart is obviously irritating not my belly but maybe my sphincter. Maybe I should do an intentional trial of pure water or saline rinse of my last enema of the day to see if the rinse might calm down my sphincter. Interesting plan. Just from tactile (hand) inspection, as I can't see it, I'm afraid I may have a small (few mm) right posterior lateral hemorrhoid that my favorite surgeon may be fixing soon. That may solve the whole problem.
As far as retention and absorption and post-enema urination, I just intensely enjoy the feelings of retention of any type of enema, from about 2-5 quarts. My usual is normal saline plus Castile soap. I have a salt meter for my pool, but haven't officially tested my enema water, which now that think of it is a good idea. So on a normal enema, the salt is roughly isotonic plus some additional Sodium from the Castile soap. Many soaps are Sodium or other anions ionically bonded to a large soap cation, but I haven't read the Castile content yet. As a result, my enema solutions are probably normal to slightly hypertonic and don't engender a great deal of water absorption across the colonic wall. Thus, I don't experience an excessive amount of post-enema urination accountable from the enema.. Another experiment I'll do is just a pure water enema held a long time (3-4 q held 30-60 min) to see what happens to my hydration status.
I wrote this as a reply to Gallonist after his reply to me about his daily gallon practice, but I don't see his reply now. I'll post it here and look for his reply, as he's the one who asked me about enema absorption and hydration and urination. If the mods see two copies of this, just delete the one not for Gallonist.
More later,
Eric
Dick