In hunterXhunter, episode 36 Gon is playing a game and he has to guess in which hand a coin is. From your replies I guess that in order to say that the coin is in the left hand he should say "hidari ni"; however, in this episode Gon says (several times) "hidari de".
Does he use "de" instead of "ni" because it's an anime so he's talking a kind of slang, or because in this case it's right to use "de" instead of "ni"?
(sorry for my grammar
... I hope to have written in a comprehensible English... if not tell me and I'll try to rewrite the question)