Although the answer is you can't... I'm guessing you want this as it is easy to accidentally dump the contents of one directory into another and completely mess up Windows... or whatever you were working on.
If this was entirely accidental (e.g. laptop touchpad is highly sensitive sometimes and a "scroll" becomes a click drag and drop...) there's not much you can do.
However if this was the result of an intentional drag... and it got dropped by accident... I'd like to make a suggestion as to a habit to start using.
If you right click to drag and drop... you are presented with a list when you drop for what you want to do... copy? move? create a shortcut?... or cancel! (clicking elsewhere or Esc also halts the action)
If you do this out of habit, you'll stop most accidents.
Finally, if you did accidentally move a pile of files somewhere you didn't plan to... you can use Edit > Undo... or click CTRL + Z
The only trick is you need to catch that you did it right away... ;-) thus right-clicking to drag is much safer