Push-to-mute shortcut?

[DarwinAwardWinner]

It would be nice to have the inverse option of push-to-talk, i.e. push-to-mute, in which the microphone is muted while the shortcut is held, and then unmuted when the shortcut is released. This is useful e.g. when you have a cold and want to mute your coughing and sneezing while otherwise staying unmuted.