Technically used (obviously) for using Portals in a clever way, However this phrase may be used to describe thinking out of the box in general, or a replacement for that phrase. So basically it functions as a synonym for Thinking out of the box. Often used as "Now you're thinking with portals!" etc.

When you eat dirt for the first time and leave your family to build a shack in the woods

When you use portals in a clever way.