Watch the Dorian Flat 2 online guitar lesson by Bruce Arnold from Total Modal

Dorian b2 and Lydian #5 are again difficult modes to get in your ear but be patient and play along with some of the vamps to understand the sound. To memorize the Dorian b2 think of it as a Dorian mode and then just flat the 2nd. Use the dominant 7sus4 vamp to play the Dorian b2 mode.
The Dorian b2 has no avoid notes when used over a 7sus4 chord. You can also try putting the Dorian b2 over the minor chord vamps. In that case the b2 will be an avoid note and will need to resolve.
STUDY TIP .....
What tools do you need to be a great musician? Below is a listing of the elements needed to express yourself with music
1. Drive and dedication
2. A need to express yourself artistically
3. An ability to use your ear to hear music around you and play the music you hear inside of yourself.
4. Ability to read music
5. Technical facility on your instrument
6. Internalized understanding of musical concepts such as rhythm, harmony and melody
7. Mental knowledge of the theoretical relationship within the music you are playing.
For each of the aforementioned areas the more you neglect a particular aspect the more you limit your ability to express yourself in any musical situation you might find yourself in. We should also mention Life and its demands upon your time. How you are able to balance your schedule so that you can live in both worlds is a serious issue. How you structure your practice time is key to resolving this issue.