Use the all items x999 cheat code or you get in the lottery if all 5 numbers match.
4 all i know each Pokemon trainer games have only one Exp. Share in the whole game
An exp share allows you to share exp with another Pokémon. You can get it in Pokémon Diamond Pearl and Platinum near Eterna City.
From a scientist.
you could switch Pokemon in battle then all Pokemon that battled get exp or you could get the exp share and give it to one of your Pokemon
use the exp share
Once you get 35 Pokemon in your PokeDex, Prof. Rowan's aid will give you the Exp. Share in Eterna City's gatehouse.
give the exp share to a weak Pokemon when you use any Pokemon to fight exp goes to the fighting Pokemon and the 1 with the exp share.
The exp share will give only the other Pokemon exp not the 100 because it is impossible to gain exp on a 100.
give it an exp share or put the Pokemon first in your party and then switch it out with the other Pokemon. hope i helped.
give the Pokemon you want to train an exp share then put your strong Pokemon first on your team and train on high leveled Pokemon the Pokemon with the exp share should level up by itself!
In diamond and pearl it is 35. an it is an EXP SHARE not and esp shard.
trade a Pokemon from another game that is holding exp share to the game that you want it on.