Cover to mute

I did some tests and it seems that this feature will only work during or right after a recent notification. When I try it when the Watch is just sitting idly, nothing happens. If I FaceTime call my phone from my iPad, and cover the Watch while the Watch is ringing, I get the vibration, and the Watch goes to mute.

Try again after restarting it.

I used it yesterday, so far as I'm concerned it mutes a single occurrence which means IMO it's not really for notifications but for incoming phone calls.

Yeah, nothing happens when I put my palm over my Watch either and cover to mute feature is turned on.

From Apple: "You can quickly mute alert and notification sounds by resting the palm of your hand on the watch display for at least three seconds."

What does that exactly mean? Can we mute the Watch permanently with the palm or not? Seems to me that the alert or notification sound is long gone after a 3 second palm...so what's the point.

Note: A coworker tried the feature and works fine on his watch. A 3 second palmed did mute his watch. Not sure why not mine or the OPs.

When the option is enabled, Cover to Mute automatically places your watch into Silent Mode when you cover the display for at least 3 seconds immediately upon receiving an alert. Once Silent Mode has been enabled in this way, it must be turned off manually in order for audible alerts to resume.

More information:

Adjust brightness, text, sound, and haptics on Apple Watch - Apple Support

Seems like you can also activate Siri by holding down the digital crown and then resting your palm over the phone.

Siri can be activated just by holding down the Digital Crown:

https://help.apple.com/watch/#/apd6db6dfa52