stamina hmmmm lets see for field trips, chocolate (tried all sorts, generally cherry ripes and kit kats - less mess on fingers) , potato crisps (barbecue or cheese and onion mostly) (for fatty warm glow) or cheezles, iced coffee (farmers union of course) or the chocolate one in a small carton, used to make thermo's of tea, but too lazy these days, a small bottle coca cola for some caffeine, lollies, those jelly type ones like starbursts or the new natural confectionary ones, with snakes ect. for a sugar/glucose hit, and cigarrettes and oh, excitement/enthuisiasm
dont forget to floss and neutralise ph in mouth (tapwater and chew gum) when ya get home tho! or your dentist will love ya! EDIT: i should know it took me 4 root canals to cotton on to this