Hey there is a good youtube of Joy featuring the Love Band and Doug playing a Trussart Steel Deville. You can pick up the basic riff off of that footage.
It is actually a classic blues riff with a C note on the A string pulled off to a basic closed A5 followed by a step down to a bent G note on the E string back to the same A. Its all feel and not that hard to execute. Doug superimposes a lot of double stop / 2 note chords over the baisc riff on the 2nd and 3rd Strings and then impropvises quite a jazzy solo. I love the Fillmore version best.