When somebodyy looks at your screen while playing a multiplayer videogame on the same TV. It is used mostly when you see that somebody is in your general area with your peripheral vision and you decide to go kill them by looking at their screen to see where they are. Looking at their controler also gives you the advantage of when they are going to attack. Screen rapers are often caught when your running up behiend someone and they turn around for no reason and kill you unexpectedly and use they crappy excuse that they saw you on radar.
Screen rape!! Screen raper!! You just turned around for no reason right as I went to punch you in the back.