Spray paint is used to communicate with other players. You must be connected to the internet to access this though. When connected press B on the gamepad near a wall and a menu of icons will appear.
Reading other peoples messagesEdit
To read other peoples messages you will have to scan a room. This can be done by any level of scanner so if you have just started the game you can read messages just the same as someone who has nearly completed it.
Deleting your messagesEdit
If you write a message and you're not happy with it you can delete it. Do this by scanning it and press and hold delete and the gamepad.