I'm writing a song in C Aeolian/Dorian (the verses are in Aeolian and the chorus is in Dorian). And I came up with a weird chord progression for the end of my chorus:
Cm Eb F Bb7 C D
My question is why does the D sound right at the end? Usually, songs end with a tonic (I, vi, etc.), but the D here, as far as I can tell is a dominant of a dominant (V/V). It's the dominant of G which is the dominant of C. Just looking at this progression, it wouldn't seem like the ending would sound resolved, but when I play it, it sounds great. Can anyone explain the theory behind this?