The aft stern line keeps the bow from swing into the dock. As others have observed, we have an amidships spring line which helps from "torqueing" the bow inward more.

If the current or the wind doing odd things, it can change a bit. With a wind pushing you "into" the along-side dock, of course you may modify your plan. If a strong current is pushing "aftward" (so the spring is "lazy", then you may) you might adjust your approach.

There is an old school approach which uses a line lead from a "normal" main coaming winch that some people use when single handing. I've never tried it, but it sort of does the same thing as the single spring line with the engine in idle, and the rudder "kicked" away from the dock. I've always found that a bit un-nerving to use because if you miss the dock cleat, it can cause a "bang" :^))).