Photoshop users?

[honduh440]

After I mask off an area and go back to the standard screen and I persue filling in the area I masked off, how do I get it to where the color does not go outside of the lines masked off? I know their is something you click, but I havnt been on photoshop in a while now. Does anyone know? also I am using Photoshop CS.

[honduh440]

?

[XCAdam89]

Before you begin, duplicate the layer. (Right click on the layer, hit duplicate layer) and then if you use the eraser tool if it goes over, it wil not erase the backround.