Why bother? It’s not called an “AUTOMATIC” transmission for nothing. The only time you should need to downshift it manually is when descending a long grade.
For that matter, why downshift a manual? Brakes are far cheaper than clutches and transmissions. I say that, and I can double de-clutch downshift with the best of 'em. Unless you’re in a really tight situation where engine braking is needed to stop shorter, it’s just not needed.