Emptying the black water tank is not my favorite task. But I do enjoy the convenience of having our own bathroom, so this is a task I readily accept.
To make the job more bearable, I always wear disposable rubber gloves.
I start by simply opening the valve of the black water tank. If we've stayed at the camp for any length of time, there is a "whoosh" as the waste rushes from the tank through the hose. At this point, I simply walk away to tend to other tasks to allow plenty of time for the waste to completely discharge.
Once the tank is empty, this step is pretty much complete, and the tank is ready to be "flushed".