On the violin, by sliding a finger up or down the string. On the piano, by gliding up the keys with the nail of the middle finger or sliding down the keys with the nail of the thumb. For 10 points -- name this technique, a rapid sliding up or down the musical scale, denoted 
On the violin, by sliding a finger up or down the string. On the piano, by gliding up the keys with the nail of the middle finger or sliding down the keys with the nail of the thumb. For 10 points -- name this technique, a rapid sliding up or down the musical scale, denoted by a vertical or diagonal wavy line.
On the violin, by sliding a finger up or down the string. On the piano, by gliding up the keys with the nail of the middle finger or sliding down the keys with the nail of the thumb.