You take a hairband, a thick one, like you would use to wrap a womans hair in a pony tail.
Then, you slide it over the neck around the first fret. What this does is mutes the strings you arent playing, but it can also take away from one's ability to be able to mute strings.
When you're done with your tapping/sweeping lick, you just slide the hairband off of the first fret onto the headstock and continue playing.
Sometimes I hit notes only dogs can hear.
