When someone is really, really, REALLY high or drunk. Auditory and visual functioning are impaired to comedic levels and the individual expresses a desire to stay in a place where other people want to leave OR leave a place where everyone is staying because the alcohol and drugs are impairing their thought processes and physical stability.
Jason Red was already clacked, but the Twerk Queen twerking on him pushed him over the edge and made him the party early. "I'm clacked! I got graduation tomorrow and I'm hungry."
Billy Blue was so clacked that he had to have an escort (Zack Black) to prevent security from kicking him out because of his boisterous and rowdy behavior.