Still more?  What?  It hasn't all been said on the topic!  No, I add
to the complication of terms.  Stringed instrument players, balalaika
players in particular, use two types:

If one presses downward on the bridge, the tension is lowered, and
the note drops in frequency, but then only returns to normal.  Repeated
plucking is _not_ done during this, or the effects get too clouded and
it don't sound good.

Some players press the string with the heel of the hand, above the
bridge section.  This tightens the string, hence causes a rise, that
again returns to normal.

The real artist (ask him) insists that both must rapidly be done,
to get the really good up and down variations in frequency.

In all cases the note is only plucked once, and then the hand used to
press the sounding board, or bridge.  Or, yet still another variation,
the hand is merely cupped around the sound hole to vary the amplitude.

Will Herzog, K2LB
Rochester, New York, USA