When you get so high off your ass you think your a lemon, and want to juice yourself. Another possible effect of the Lemon High is the creation of random non-existent foods.
Guy 1: Man I want those WonkaChunk Peanutz!
Guy 2: Dude what the hell are you talking about?!
Guy 1: I have no idea I have a Lemon High, and I just want to juice myself.