To get so incredibly drunk that you become totally retarded that you begin to speak in jibberish, randomly spouting pterodactyl-ish noises. Other signs of being Schneidered include: making faces which would only otherwise be made by someone having a continuous mild stroke, excessive nipple poking through one's shirt, inability to pronounce the letters "R" and "L", an odd facination with how hot your sister is, an extreme pride in having a brother who is a Pike at Auburn, inability to write emails or get laid, excessive sweating and anal leakage.
A&F model: Wow, that guy just drank an entire fifth of Malibu.
Hollister Model: Yeah, that guy is gonna be totally schneidered in a few minutes. I hope his hair gel doesn't run into his eyes.