Bottleneck Slide

Occasionally a bottleneck is used on only the highest two strings of a guitar in standard tuning, usually in live performance to introduce just a short passage of bottleneck effect into a piece which otherwise consists mainly of guitar played in standard fashion.

The main technical challenges with slide guitar playing are,

1) Intonation (playing each note right at the desired pitch, not a little flat or a little sharp)
2) Muting undesired strings.

Slide guitar places greater demands on one's ability to mute strings than standard guitar. This is because the slide is always pressing down all, or at least several of the strings, but not all of those strings are necessarily intended to sound at a given time. In particular, on standard guitar, a fretted note stops more or less automatically when you are done with it: you lift the finger, and that kills the note. On slide, the note keeps ringing until you do something definite to stop it. You can touch the string with a fingertip of the picking hand, or you can lift the slide and damp with a fretting-hand finger. The first method is more selective, the second stops all sound. It is easy to get a howling mass of notes on slide guitar. Playing a melody with well articulated individual notes requires more skill than may at first be apparent.

Slide guitar is most often fingerpicked, with or without plastic or metal picks on the thumb and fingers. However some players use a flatpick (plectrum).

The bottleneck or tube type of slide is usually worn over the ring (3rd) or little (4th) finger. Wearing on the 4th finger has the advantage of leaving one more finger free to fret notes if desired. However some players feel that they get better control using the ring finger. Most instructors recommend letting one or more of the fingers in back of the slide rest lightly on the strings to help mute unwanted vibrations.