It depends on the purpose of the retention enema. For example for liver cleansing and using a small volume coffee enema, say of 2 cups, it is best to remain on your left side and keep the solution in the rectum and the sigmoid section. This enema is usually retained for 10 to 15 minutes.
However if you use a large volume coffee enema say 1 quart, then my suggestion is that you retain it for 20 minutes, 5 minutes on your left side, 5 minutes flat on your back with knees raise and a small pillow under the buttocks, and, 10 minutes on your right side.
Yes, there are several type of nozzles for retention enemas, most of them are inflatable nozzles. These inflatable nozzles usually remain in your rectum until you are ready to expel the enema.
For more info please read my blog titled “My challenge” link below.