Sounds like an enema series might be just the thing for you.
If you mean by "store bought" the Fleet enema in a plastic bottle, there is a better way. Go to any large chain drugstore and purchase a fountain syringe set. They run $ 6.00 - $ 8.00. They will contain a hot water bottle with standard twist plug or an open mouth bag. There will be tubing and two nozzles . ..adult enema and douche. Some of us prefer the douche nozzle because it stays in better. Use a good lubricant and you will have no difficulty.
I have been taking enemas off and on for over 60 years. They have been of great benefit to me.
People have their preferences. You will develop your own. I usually do a series of three enemas. The first is with Dr. Bronners' Peppermint castile soap. . a couple of capsful. Then I do two and sometimes three rinsing enemas . . .plain water.
Read through this forum. You will find a LOT of information.