Watch the The Greasebox online guitar lesson by Robbie Calvo from 50 R&B Licks You MUST Know
I start this lick with the root note of the chord, C and then play a major 3rd double-stop idea with my first finger. You'll want to add a partial bend to these two notes to make them a little dirtier.
You'll notice from the tab that I slide into another pentatonic shape below where I start to get some nice glissando into the lick. This is a great way of combining your minor pentatonic shapes and moving outside of the "boxes".