How does this work?

If you want to switch devices while logged in, just log in on the new device. A pop-up will ask if you want to transfer your active session.

Press 'Transfer', and you'll be logged out from the old device. Your tables will open on the new device, so you can join right back in. You can keep the action going with no interruptions.

You can jump onto your mobile device as long as you've got a connection. It works the other way around, too.