EzekielRaiden
Follower of the Way
Perhaps a better way to phrase what I said above:I'll sketching something up when I get some time. Then maybe it will make more sense.
The secret to hummingbird flight is that they have a specially-adapted rotator cuff in their shoulders, allowing them to....rotate the wing in its socket. Meaning the wing is, functionally, bidirectional: it points forwards when it needs to point forwards, and backwards when it needs to point backwards.
If your concept makes a hummingbird dragon, the wings no longer point any specific direction between forward vs back. They point whichever direction the dragon wishes them to point. Hence, bi-directional.