Watch the Double Stops online guitar lesson by Brad Carlton from Guitar Lab: Big Blues & Beyond
This lesson covers double-stop licks in which the b5 is the lower voice. The sound produced with this technique will remind you of B3 organ style playing.
We'll begin with the b5 of the C blues scale 6th string root form in the ninth fret of the 5th string. This will be the lower voice. Then you'll play the C blues scale that exists above it on strings 4 through 1.
This same approach can be used in the higher octave with the b5 occuring in the eleventh fret of the 3rd string. You then combine this b5 with the C blues scale above it.
The b5 is rather sinister sounding, ao apply these licks judiciously.