Quickly Mute and Dim Your Watch
One of the more useful but hidden features of the Apple Watch is the ability to quickly dim its display. Just place your hand over the device quickly to get the display to go back to sleep (perfect for those times the display wakes up accidentally).
But this feature actually goes a step further than that. If you want to quickly mute your Apple Watch, just hold your hand over it for about three seconds — you should feel a haptic feedback when it’s been silenced. You can edit this in the Watch app, just go to My Watch > Sound & Haptics.