ERS

Stands for "Excessive Reloading Syndrome". Used in FPS games to describe someone that reloads whenever they shoot a bullet. Usually is a result of dying from not having enough bullets in the clip to kill someone, and then being killed by said person.

"I always reload after I kill someone, I think I have ERS."

Guy 1: "Dude, this guy reloads too much!"
Guy 2: "Yeah, he has ERS"