Being poserrific try as hard as humanly possible to correctly pose others behavior. They maintain the highest amount of sarcasm possible whilst doing so, in a desparate attempt to be somewhat believable. Often found in those who are stuck up, emos, scenesters, those that lack confidence, 16 year old girls, 13 year old boys, and anyone else who is trying too hard. Those who correctly maintain a poserrific state for long periods of time are "doing it right."
Alex pretended to laugh along with the crowd, but unbeknownst to him, the entire crowd knew he was being poserrific. The crowd then proceeded to laugh at, throw bottles/stones at, hang, tar, feather, crucify, and set fire to alex for his poserrific behavior.