I finally tried it and what an amazing experience this was! The "wow" factor was pegged! I decided that I would do this with 2 quarts of water and with my bisacodyl/sea recipe salt mixed in. I didn't want to go over that, because I'm still experimenting. I did the usual thing when I administered the enema and waited. I did have a fairly full bowel and colon, so after putting it all inside of me, I experienced moderate cramping as the stuff was going in.
About 5 minutes after I closed the clamp and got into different positions, I was to the point to where I couldn't hold it in any longer and needed very urgently to sit on the toilet and expel. I got on the toilet, let loose and about halfway through the first expulsion I tightened up my butthole to stop the release. I did this to relieve the excessive pressure built up inside of me. This produced a fairly large, but short stream of liquid and a few small solids.
I knew (from the last experience) that the cramping, tummy rumbles and sudden urge to go would be setting in, but I didn't know exactly when this was going to happen. I started pleasuring myself and got nearly to the to the point of climax. I kept his up, but maintained control so I wouldn't climax (with experience, I'm very good at this). A few minutes later, the cramps started setting in and pretty hard. This and a pretty good tummy rumble got me aroused even more. Then, the sudden urge to go came very quickly.
I tried my best to hold it in and I was doing a very good job at it (only a small amount of liquid trickled out of my me). When I finally reached the point of orgasm, I totally lost control of my bowels! First a spurt of liquid shot out of me. Then immediately after that, about half a dozen of much larger spurts of liquid with a lot of large/small solids and some juicy toilet farts came out, all within a fraction of a second of each other! It was exactly like others explained in this post, a very intense, explosive and a powerful start/stop expulsion! My orgasm was very intense, so much that I squirted a large stream of love juice halfway across the bathroom. I've only squirted once in my life and that was done with the help of a battery powered toy. I only had to use my 3 finger technique (and an enema) with this one.
Unlike what some the guys have mentioned in this post, I enjoyed every expulsion that followed and never lost any interest during my entire enema session. After about an additional 3-4 large "chunky" expulsions, I wiped and flushed, but had to hurry back to the toilet 15 minutes later to go some more. During this trip, I pleasured myself again and enjoyed 2 more (non squirting) orgasms!
So with my experience, my strategy was to expel (some of the first expulsion) enough to relieve the initial pressure, hold the rest of that expulsion in, start the masturbation, wait for the cramps and urge to go to come (the liquid and poop will want to come out and the urge will get stronger and not let up because of the bisacodyl), keep holding it in and get to the point of orgasm. After that, everything will happen automatically. There is a timing factor and I had to plan it all well, but for me it wasn't too difficult to figure out.