Do you have any tips on how one could use them in songs?
no, but i can explain why they have a word for it. it's because someone was noticing that a 'minor scale', in C minor, for example, seems to naturally want to contain these notes: C, D, Eb, F, G, Ab, Bb, C. But what happens, often enough, is you go to your big strong 5 chord and it's G7 which has the note B natural in it. and the melody may hit that B natural too. so the person was looking for a way to explain this so they said 'what the heck, just call it a new scale and say the B is always in it.' But the truth is, the B only really will be there when you hit that G7 chord (or Bdiminished or whatever). When that type of chord isn't there, you could easily have all your Bb's as normal.