Pull-offs
This almost the opposite of a hammer-on. Start with your first finger at the 5th fret on the top string, and your third finger at the 7th fret on the same string. Pluck the string to hear the note at the 7th fret, then pull your third finger away from the string in a sideways motion. Keep some downwards pressure on the neck with this finger so that when the finger leaves the string it performs a kind of pluck of its own, and you hear the note at the 5th fret. As with the hammer-on, you hear two or more notes for every one that is picked.
Example:
NB: h = hammer-on, p = pull-off
E---5h7p5h7p5h7p5h7p5h7p5h7p5-------------- B------------------------------------------ G------------------------------------------ D------------------------------------------ A------------------------------------------ E------------------------------------------