The plates are struck against each other and separated immediately (which amounts to a glancing blow).
The sustain of notated whole notes or tied notes is not usually damped; the cymbals are held until the note has decayed naturally. If eighth, quarter or half notes are written without a tie the cymbal is damped against the chest to define the proper note length.
For very quiet notes the plates are not brought into full contact; instead only a particular point is struck, usually at the top where it is easier for the percussionist to control the point of impact. This produces a very quiet note, which nonetheless still differs greatly from the sound of the suspended cymbal.