This one is simple to do to pull off. Under default controls, throw is B+C which equals Y+B on the Xbox controller. I found it best to set throw to a trigger, in my case RT.
Plug in a second controller and do a Versus match. As soon as it starts, move your characters together and have the second character attempt a throw. As soon as you press the throw button on the second controller, press it on the first one. Your character should knock the opponent away with a blue flash and you'll see Throw Escape appear on the screen. Repeat 4 more times and you'll get the achievement.