Watch the Combine The 6th And 9th online guitar lesson by Rob Garland from The Guitarist's Pentathlon
As well as the 6th this application also includes the 9th, added to Gm pentatonic and played against a minor vamp, Gm7. These tones are good friends and work well together. You can look at the chart for locations of the 6th and 9th but for extra credit, find them on the neck yourself! You'll be looking for an E and an A.