A descending slur (Pull-off) is simply the opposite of the above, the slur begins on the higher note, and it is common that the finger pressing the higher note actively plucks the string as it lifts, causing the string to vibrate from the fret that the lower finger is depressing.
A descending slur (Pull-off) is a technique in which the finger pressing the higher note actively plucks the string as it rises, creating vibration from the fret being depressed by the lower finger.