I've been an enema afficianado since my teens. Started enjoying larger amounts in my 20's (up to 3 quarts). When I convinced my wife to give me enemas, I was able to take even larger amounts of 4 plus quarts.
A few years ago I was holding almost 5 quarts and was massaging my abdomen when I had a strange feeling . A bulge started on my lower belly. I immediately released the water and was able to push the bulge back in. Over the next few days it bulged a few more times. I went to a medical supply store and bought an elastic truss to help hold it in. It sort of worked for a while, but I finally had to see my doctor.
He referred me to a surgeon and he was able to repair it, but it was serious surgery. The hernia had dropped down to my scrotum. A little scary and lots of pain for a while. I haven't lost my enjoyment of enemas, but it has been a slow and careful return. My advice to everyone is that you don't get carried away with high volume. I was lucky--things could have been much worse.
The old axiom, "everything in moderation" is a good one to follow.