How do I do the balloons effect in iOS 10's Messages?
1. Write your message (you'll add your effect when you're ready to send) 
2. Hold down the blue, circular send icon—&quot;Send with effect&quot; options will show
3. Select the &quot;Screen&quot; tab and swipe between your five options. Press the blue icon to confirm and send!  
It only plays once, on arrival, and does not replay so enjoy the moment. As of now, the effects can only be sent and played back on iOS. (They'll show as plain iMessages in the macOS app.)