You can do it no problem with a stick, but it is living dangerously with an automatic. Couple of reasons:

1. You can match revs with a stick, you can't with an auto.

2. The clutch takes the brunt of the downshift on a manual, and that is completely driver controlled. You downshift with an auto, the gears are pretty much locking with the engine still turning the torque converter. Nothing like a good ole "thunk" to shake the cob webs off your transmission.