That's where the prop walk on my boat is useful. It's not backing up from a standstill, rather it's converting forward momentum into reverse momentum. If I could put Genes slip off my starboard beam while I'm slowly underway, and there was enough space to be steering and arc to port,...I could use reverse to rotate the stern counter clockwise as it slowed the boat. With the remaining momentum now carrying the boat into the slip, gentle reverse can finish tucking the starboard side of the boat onto the dock.

I see this maneuver done often with an old schooner in our harbor. With a full keep/prop in aperture, they have to get into a narrow slip space. After watching the crew do it well for quite some time, I tried it myself(when no boats were around). It worked!