Just keep it about the receiver and not about the enema itself
If the receiver has had previous enemas, try to get them to tell you about it. You need to make decisions on volume and height(flow rate) and exact chemistry of the fluid based on that.
Emphasize the 3 rules of enemas. 1)Try to take the full amount. 2) hold it as long as you can. 3)if you really need to change position, expel and try again.
You want to get the receiver's full cooperation. allowing them to watch the preparation, and help out with filling and hanging the bag can go a long way!
An older child, 'teen or certainly an adult should be offered at least 2 nozzle options. Same for position. offer 2 or at most 3 possible positions, and explain that they MUST remain in that position for the duration of that round,
Younger children can feel overwhelmed so limit that choice to no more than 3.
Treat the bag, can or bulb as a tool. You want to take care of your tools, but it's not about that, it is about the PERSON getting the enema.
The water should be WARM BUT NOT HOT to the touch of the receiver. That's who has final say on temperature.
This will make you a good first time giver!