My current thing is to decongest my liver and get the bile flowing. My blood/body is heavily toxic to the point that I can't tolerate 90% of vitamins or supplements. I am planning a daily coffee enema ritual.
Regarding kefir, Have you thought of Water Kefir? Very simple and cheap to make. Check this video out:
I felt candida die off effects with as little as 4 ounces of kefir which was fermented for 3 days. Powerful stuff.
It seems your problem has to do with perforated lining of the gut because you feel relief after voiding; your body doesn't want the waste/food in your intestines. The waste maybe irritating the lining and the body feels its better out than in so you have trouble closing the sphincter. I have read about a 3 day fast on Slippery Elm Bark- Gruel dramatically improving leaky gut/ intestinal shape. I haven't tried it, but if you're looking for quick relief it maybe something to consider. Search CZ for "slippery elm bark fast". If I had this issue, I would do a colonic/colon cleanse followed by slippery elm gruel fast followed by adding fermented foods into my diet. Good Luck!