I've practiced this a few times with a soapy series. I'll prep about 3 qts with Dr. B's peppermint and take a quart at a time.
Most of my time was spent holding each quart; i aimed for 10-15 minutes each, and refilling within just a few minutes of a decent (but not total) release of the prior quart. As my hold time decreased, my releases came more quickly, allowing me then to get the nozzle & next quart in.
One time turned out really well. After the 3rd soapy release, I took a 3 qt very warm plain rinse. Really easy & quick going in, good gurgling, and I held for less than 10 min. A very strong expulsion began - felt like 2 qts all at once - then a momentary pause - and resumed with one great blast and approx another qt emerging from the deep fully emptied me.
Altogether, about 6 qts of soapy + rinse in just about an hour, and I felt wonderful.
Since then, still a good performance but not as good as that one hour. But I'm enjoying starting the new bag right after just a good release wave, similar to @sers.