The left/right side theory about the coffee enema never applied to me.
I used to do my coffee enema after a home colonic, lying on my back on the colema board waiting for the bile duct to empties and feeling a squirting sensation in the area of my right rib cage. I say this happened 95% of the time. IMO, it’s worth it to toughen it out for that 15-20 minute grueling duration. Also breathing in/out helped a lot.
And seeing all the junk hosed out was a delight always and also a horror sometimes.