Over the years I have used a variety of soap solutions for my "soap suds" enemas. Ivory bar soap swished around in a container until Gray & slippery continues to be a favorite. I am somewhat puzzled over the myriad of reader comments regarding the exact formula of current versus former soap, I have to say that I have not noticed any difference in the fifty odd years that I have been using this product for enemas. They have all been simply great!
That said, I often myself switching to a jar of enema soap that I keep prepared in my cupboard made from leftover pieces of Glycerin based natural fruit scented bath soaps that my wife buys from one of the local upscale bath shops in the mall. These semi soft bars lend themselves to being mixed with a small quantity of water, mashed up into a paste like consistency, and stored in a closed jar for future use. Adding several table spoons of this mixture into four quarts of very warm water makes for a very nice, old fashioned soap suds enema.
When I have the time for a somewhat messier clean up, I like to add several ounces of Olive Oil to my soapsuds enemas which increases the efficiency by liquefying the stool and, better lubricating the rectum, for deep colon tube insertion. ,