I have never used a balloon nozzle and neither has my Father.
Only experience my father has ever had with one is one enema session with my mom. She lost a 2-Imperial quart enema Dad had just given her.
She was determined to re-do it successfully and she stepped Dad through getting a double balloon nozzle into her, inflating it and hooking it up to her bag. and ultimately getting the enema into Mom!
When she first got the balloon nozzle out, she held it up in front of him, explained how it works, explained how that "Small tube in the middle" should the part that passes her rectal muscle. then she explained how to get the front balloon inside her. She even inflated it outside her and let him try.
She also said, Once it is inside me, my body will put a little back pressure on it, so it would be a little harder to inflate, but he still should not force it.
She said,"The inside balloon I can feel easily, the outside one I can tell it's there but it's hard to tell how much it's inflated. Like any balloon over inflation can ruin it! "
"Here is what I want you to do! I will get into knee-chest position, and you need to get it in me just like I explained then set it to inflate the inside bulb. when it is ready to inflate, watch my left hand (She was right handed) . If my thumb is up, squeeze the bulb all the way. If my thumb is pointing to the side, squeeze the bulb a little, but not too much. If I fold my thumb up against my hand, re set the valve for the front bulb. Then go two pumps, and stop!
The back one should not need as much. When I got that barium enema done they used a balloon nozzle that only had the one balloon, and it was small. That was holding back barium sulfate, which is heavier and comes out easier than soapsuds!"