Tapping -

"Tapping, also called tap style (tapstyle), touch-style, and two-handed tapping, is a guitar playing technique where a string is fretted and set into vibration as part of a single motion of being tapped onto the fretboard, with either hand, as opposed to the standard technique of fretting with one hand and picking with the other. Tapping is the primary technique intended for some instruments such as the Chapman Stick, and is the alternative method for the Warr Guitar and others. Tapped passages incorporate the techniques of hammer-on and pull-off, but with both hands freed to produce notes. Some players rely extensively or exclusively on tapping. - Wikipedia"