Watch the El Mariachi online guitar lesson by Jeff McErlain from Play in the Style of Billy Gibbons
I've talked about this in many of my courses and videos and that is the idea of tweaking the flatted third of your minor pentatonic scale. It is an essential technique to have under your fingers and one of those rare things that will make you sound better immediately. G minor pentatonic is spelled G-Bb-C-D-F, the b3 is the Bb. The Bb on the Gm chord used in the progression fits just fine as a chord tone, but can sound a little lifeless. It is customary in the blues to bend that note a slight bit - I'm talking about a quarter step at most. We want to be careful not to bend too much as we do not want to bend it to the natural third because that it will sound wrong and ugly. As you can see in the lick anytime I am playing a Bb I am tweaking it a little bit. It is important not to release this bend as that ruins sound we are going for, that slight lift in the note that implies it is going somewhere. In Eric Clapton's autobiography, he does not speak about music all that much it was mostly about his personal life and addictions. The one paragraph I being actually about music he discusses this technique and the importance of perfecting it. He said he spent hours making sure he had this right and I suggest you do the same!