We - my ladyfriend and I - like to use a glycerin solution for our enemas. She can take a 30 percent glycerin while I have to do with a 20 percent to avoid nightlong cramps.
We also use soapsuds - actually a handsoap with honey and glycerin in warm water. From time to time we start with injecting lukewarm salad oil into the rectum, to make it more receptive.
What is your poison?