I replied to this with my own experiences, but I remembered my first girlfriend told me that when she got enemas from her mother, her Mom used to mix up a strong soap solution and sit her on the toilet. She said she cried and begged every time, sobbing, saying, "Mommy, it hurts!"
Thinking about that, I realized that I never used soap in her enemas. She actually asked me to give her an enema the first time I did, after I had asked her if she had ever had one, and she initially rejected the idea, after telling me the story I just related. However, she evidently got super constipated a few days later, and (with a hugely red face) asked me to give her an enema. I was beyond pleased, and our date became a treatment. It was my biggest fetish, and I got to do it to my girlfriend... my point is that she never cried, and I gave her many enemas-- but I also never used soap and always gave her her enemas lying down bottoms up, or on her back, legs up. I never gave her her enemas on the toilet. The one thing I hadn't learned as a teenager was that even a small slender girl could take a 2 quart enema easily--she might not think so, because there's a certaian amount of panic as the waater fills you and cramps start. But at least two quarts twice or three times, is the only way to get a thorough cleanse, rather than emptying just the rectum. When I finally told her "you have to take it all," she took the entire bag with no problem. She remarked " when you know you have to take it all, it all goes in." I found that remark to be true in every case. A gentle but very firm administration is the way. I remember, much later, giving a full bag enema to a Filipina who was probably 5' 1" or 2" and couldn't have weighed more than 120 pounds. She said, "It felt good." My experiences have convinced me that getting the girl's colon completely full is the best way to make the enema truly effective. When I can get her to take more, I do. The limit is probably about 2-1/2 to 3 quarts, based on what I've found by giving many, many enemas to women. It's important that the colon be completely filled. I have even given 2 quart enemas to quite constipated women without them experiencing a great deal of stress. The same of course, goes for me. A full colon empties completely...