when you have to study (for a test, quiz, etc.) and you cannot stop eating useless junk even though you're not hungry purely to entertain yourself while you study
"hey look, gushers... i'm not hungry or anything but they would make studying so much more tolerable!"
-nom nom nom-
"hey look, southwestern ranch baked lays..." (process repeats)
an hour later...
"ughhh i just ate an entire box of cheez-its.. damn study munchies"