Do you need to give yourself an enema using a gravity bag system and not sure how to go about doing it? Here are some tips for using this type of enema device on your own. Use The Right Solutions You'll want to use a saline solution for your enema if you want it to work correctly since using water alone may not have the desired effects. Thankfully, you can purchase a saline solution specifically for this purpose, which should have glycerine in it as an active ingredient.