Watch the Slip Stream online guitar lesson by Robbie Calvo from 50 R&B Licks You MUST Know
The lick starts with a major 3rd double stop which outlines the A chord. The next part of the lick is derived from an A7 arpeggio.
You'll need to use your little finger for those slides. I slide into the E and G notes and from there I use the A blues scale in position to hit those cool chromatics. At the end of that run I slide down from the D to a C before sliding to the resolving double stop of C# and E. (The major 3rd interval that we started the lick with).