So, when a notification hits your phone, the Pebble immediately buzzes and lights its screen, displaying the content of that notification. It'll sit there for three minutes, then go back to whatever you were doing.
So if you were in the Music controller, you would hit the Pebble's back button to dismiss the notification and you'd see your current track again. If you were on a watch app, you'll see the watch.
Fair point about manners! The fact that the device rather noticeably lights up gives you a bit of cover though.