Can I send two separate data values through the serial port from Arduino to processing?

I am creating a project similar to this 

I currently am using Serial.write to send the accelerometer data values over the serial port to processing. I would like to introduce a button (digtal reading) where if the button is pressed the data can be read by processing and without affecting any of the accelerometer data being read. How could I do that?

[original story: Circuit Digest]

Circuit Digest 01 Dec 20:00