Watch the Down To The Final Five online guitar lesson by Matthieu Brandt from 50 Jump Blues Licks You MUST Know
On each segment in a standard 12 bar blues there are a number of characteristic chord tricks you can insert in your accompaniment. This lick can be played when you are moving towards the V chord in bar 9 of a blues progression. Or in this case when you're moving to a II - V, more common in jump blues. Make sure you signal your band mates when you want to insert this one into your backup.