Double-stop shapes occur on adjacent strings in the case of Minor/Major 3rds, Fourths etc, (or with a string between them in the case of Major/Minor 6ths and Octaves).
What is a double-stop guitar?
A double-stop is nothing more than two notes that you play at the same time. It falls somewhere between a single note (one note) and a chord (three or more notes). ... Fret them the same way that you do chords or single notes. Playing double-stops on the guitar is a great way to enhance your playing.
Why is a double-stop called a double-stop?
This is actually a violin related thing. In violin, when you finger a note it is called a stop, so when you finger two notes, it's a double stop. It's just been carried over to guitar.
What is a double-stop Bend?
A double-stop bend is where you bend a note on a lower-pitched string either a half step or whole step, and you then play a second note on a higher pitched string.