Where do you find the exp share in pokemon gold?

Well, you must know surf, and be able to get to mahogany town. Take route 43 north to the lake of rage. Surf on the lake : this only works when its raining. You should find a red Gyrados . Press a. Now either destroy it, flee when it's weak, catch it, or die. Either way, youll get a red scale. Now go to Mr Pokemon's house, and he'll want to trade it for an exp share. Press yes, and you'll get it. Same goes on heart gold. If you know another way, improve my answer. (I can't beat lance!) Hope it helped.