Now this sounds like a good contest for an E-Fest!
I was told by Anika Sondholm that some of the models in The Collectors video did get together for enema play outside of the "studio." One of the things that came up was seeing who could take two quarts the fastest. While it was non-scientific the same bag and quantities were used by the participants.
According to Anika, she won the contests, but what they didn't do was time how long it took to empty the bag with no one on the receiving end.
Anika and I tried this one afternoon when we were playing, she won hands down, beating me by a close to a minute, and she emptied the bag in just a few seconds more than free flow.
By using the E-Z-EM super setup with the 1/2" tube I was able to fill solo once when I had temperature and pressure just right in about 10'seconds more than free flow, which is quite a feeling. Nothing I want to do every time, but once in a while a turn on.
Curious as to what others have experienced.
On the other hand, many years ago, I inserted a colon tube to the sigmoid, taped in place and started a drip. I had used some plastic sheeting and towels on the bed and proceeded to fall asleep. The slow rate was such that it took nearly two hours to empty the bag. I slept several hours before I woke with a nice full feeling, and even went back to sleep for a while. It was my bladder that finally got me up, I had absorbed a lot of water. Overall it was a good release, but left me very aroused and desirous of a couple of regular enemas.