Have a pokedex of 40 when you go to the biking place you'll see dawn's dad and talk to him and he'll give it to you
Chat with our AI personalities
In diamond and pearl it is 35. an it is an EXP SHARE not and esp shard.
The exp share will give only the other Pokemon exp not the 100 because it is impossible to gain exp on a 100.
I have 20 exp shares DO U HAVE ACTION REPLAY I CAN GIVE U ONE
its a item you give your Pokemon that's too weak to battle so while you battle with your stronger Pokemon at the end of the battle the Pokemon that was in battle will get half (or all i don't really remember) of the experience and the other Pokemon will get the other half (or the same amount you would have gotten if it had battled and won)
You can get it from Dawn's/Lucas' father at the building between Eterna City and cycling road.