Yes, something interesting happens when you bring in the B or Cb chord. What happened? Or maybe you should ask what could happen after that. Many things could happen! To demonstrate the "borrowing" idea in practice: you can use the Db chord as a short step to another key, for example Eb minor or Gb major. How short or long it is and how serious you make the borrowing is completely up to you. Remember, you only played two strange notes, Cb and Gb. The rest is imagination, but to be a good story teller, you have to imagine more than was actually shown, and you continue the story following the plot you planned in your imagination.
In the following video, I highlighted the "borrowing" bits with a key signature change. The tune first makes only a one-bar visit to Gb major (six flats), and comes back to Eb (three flats). But then the next time it makes the visit longer and starts using more chords from the "other side". How long would that need to continue to say that it's not borrowing anymore but an actual key change?
Normally, a one-bar visit to a different key wouldn't warrant a key signature change, but here I did that for highlighting what's happening.
That's not the only possible "story" to think. Since you get to decide what happens after the Cb or B chord, why not make it ... a B7, and then move to E major or minor in a V-I motion. Though if you want to come back after that, you'll have to have more tricks.