In Lesson 2 on stretching, Mircea demonstrates how the first kind of stretching is achieved: with the joints of the fingers leaning left, relative to the fingertips on the fretboard. He shows the simple wrist rotation that's involved, which will enable your fingers to reach much further across the fretboard without strain.
Once you see the concept in action with two examples from the repertoire — excerpts from Granados' Valses Poéticos, No. 6 and Torroba's Sonatina — you'll understand how to apply it to a wide range of passages.