I disabled automatic spring-loaded folders. But wanted to have ability to manually activate it.

As you know if you drag one folder to another you can wait a little or immediately press spacebar. In both cases folder “spring-loads”.

But auto spring-load annoys me more than helps. Because I often need to find folder I want to spring-load. And also I have to control that I am not hovering some other random folder. And sometimes I start dragging folder and in some depth forget to control not hovering any unnecessary folder.
“And boom!” and spring-loads wrong folder.

In Finder Settings (Finder menu -> Settings or CMD+,) you can disable auto opening spring-loaded folders.
But it will also disable manual opening folder via pressing spacebar.

But the hint is to double click spacebar when you hover necessary folder. “And boom!”

Source: Mac OSX Hints