As others have said, the default configuration is to not order another if one is already ordered. In addition to that, you'll get a push notification from which

As others have said, the default configuration is to not order another if one is already ordered. In addition to that, you'll get a push notification from which you can quickly cancel the order. I don't know how the two combine though - friend presses, you cancel, friend presses, you cancel, friend presses, you cancel etc.