You know, I've never had twin screws. If you do, do you ever practice coming in with one engine just in neutral?
Well, we've had to dock twice in our twin-engine PNW boat with one engine out. A twin with an engine out is not a single.
Since the prop that's working is off to the side of the boat's centerline, it will yaw the boat away from the working prop. You can counter this with the rudders but at slow maneuvering speeds the rudders are not very effective.
So you have to plan your approach and docking with the yawing that's going to occur in mind. Ideally the boat will yaw in the direction you would turn it anyway to slide up against thre dock. Or you'll have wind or current to help you get to the dock if the yaw will be in a direction that will make it harder.
If the yaw is not in the direction you would like it to occur you have to plan your maneuvers to allow room for the boat to not turn as quickly as you'd like. Or not turn at all, in which case you have to come up with some other way of getting the boat into the space you need it to get into. So throwing lines to people ashore, using a stout boathook or pike pole, etc.
In two of our four come-home-on-one incidents, the problem was a partially blocked raw water intake that limited the flow of cooling water. The flow was enough to let us restart the shut-down engine as we approached our slip so we could use both engines for maneuvering.
Of the other two incidents, one shut down (on the delivery trip) was due to a coolant pump developing a leak through its seal and gasket and gradually dumping coolant into the drip pan under the engine, and the other was due to my letting an engine get a big slug of air during a fuel transfer "learning experience." So in each case, the engine could not be restarted to assist with maneuvering.
In the first incident the boat's yawing tendency was in the correct direction, In the second it wasn't but we had guests on board to fend us off the piling at the end of our dock and our slip neighbor if it became necessary. As I recall, I managed to get the boat into our slip with just a bit of warding-off assistance at the end to keep our stern quarter off the finger and piling.
To answer the quesiton, however, no, we do not practice maneuvering or docking with one engine in idle. We like to think that should we need to do it again (and I'm sure we will at some point) we have a good enough feel for how this boat responds to be able to pull it off reasonably well. Or realize we need to create a Plan B if getting to the dock we want to get to is too risky in terms of potentially damaging something.