The week long-lasting pants full of excitement one attains from the current popular "trend". It comes and goes with blockbuster movies, hit youtube videos and other various things teenagers worship. This usually results in a weekly trip to Hot Topic to purchase a t-shirt and/or other merchandise with the trend plastered all over it.
Jesse: AJ's goin' hard about Transformers: Revenge of the Fallen. He just bought the official soundtrack and a t-shirt.
Jeremy: That's just his Hot Topic Boner actin' up. He'll forget about it when Harry Potter 6 comes out.