Chocolate makes me sneeze. Just the first piece. Do you know how much mess it can make when your face explodes when its filled with half a drifter bar. It's a right pain in the arse.
Dont eat drifter bars then;) Now if you love chocolate that much, but it has this effect, then you may want to get tested for food intolerances, although if it shows up that you shouldnt be eating choccy, then you're kinda fked im afraid
I have a vaguely similar thing which occurs when eating a pot of chocolate mousse. (Like a yoghurt pot, only mousse). Makes me sneeze. Can be catastrophic!