Tapping is a term that describes legato techniques that employ both
hands on the fretboard. Often referred to as two-hand tapping, this
technique was revolutionized and popularized by Eddie Van Halen in the
late 1970s (“Eruption,” 1978) and taken to extremes by guitarists such as
Steve Vai, Joe Satriani, Jennifer Batten, and jazz great Stanley Jordan.
The concept is simple. Since the string does not have to be ringing when
executing a hammer-on, the right hand can hammer on to the string to
sound a note. Once the note is ringing it can be pulled off to sound a note
below it on the same string. This note may either be a fretted note using the
fretting hand or an open string. The hammer-on should slam the finger tip
down on the string with enough force to sound the note loud enough and
then remain holding the string down for the desired length of time. This
motion should come from the muscles in the fingers themselves—not the
wrist. The direction of the pull-off is a matter of preference. It is common
to pull off upwards with the picking hand then pull
off downward with the fretting hand creating a good
balance and avoiding too much bending of the string
in one direction. The finger used for single-note tapping is also a matter
of preference. If the first finger is used, the pick will have to be set aside or
palmed using the other fingers like a magician with a hidden coin. If the second
finger is used then the pick may remain in its normal position. Timing is
always a consideration, and good timing on the tapping phrases will produce
the best results. Also, dynamics are important. Try to keep volume levels the
same for hammer-ons, pull-offs, and taps.
The tapping finger in the following examples should be either the first
or second finger. Try alternating them both on each exercise. The third and
fourth finger may be used for more extreme tapping technique. Alternating
all four is also an exercise worth trying.
Download Example Audio 1...

The next set of exercises change strings while tapping. This is done the same way as on just one string. Remember, the string doesn’t have to be ringing to
sound the tap. Also, the fret hand may be moved freely behind the tap.
Download Example Audio 2...

It is common for a finger of the fret hand to do the first hammer-on onto the string before the tap as in the following examples.
Download Example Audio 3...

Here an open string is added to the exercises. There is nothing new here in terms of technique. This allows for wider
interval leaps and bigger arpeggios.
Download Example Audio 4...

Vibrato may also be added to the tap. The easiest method is to execute a normal left-hand vibrato on the string while holding the tapped note. You
may also do similar vibrato techniques with the tapping finger itself, but it is not necessary since the fret-hand vibrato is just as effective. Also, the same
technique applies to bend-tap with vibrato.
Download Example Audio 5...

The next step in tapping is to use multiple fingers of the right hand. The pick will most likely not be held anymore at this point. Muting becomes very
important to keep the licks clean, without extra string noise. Some players even go so far as to use a string damper—a device that stops all open strings
from ringing. The first step is to add one more note on one string to the previously covered techniques. Although chromatics are an obvious benefit with
up to eight notes on a single string (not including slides), the bigger benefit is a wider note range. In the following examples the suggested right-hand
fingers are indicated with circled numbers. Since the pick is not held, it is common to rest the thumb of the pick-hand on the top of the neck for balance
and placement reference. Try these extended arpeggios.
Download Example Audio 6...
This lesson comes from:

Ultimate Guitar Technique