In any case, if you want a DD tyranitar, you'll need to follow this process:
Lv50 MALE Horsea (learns dragon dance at this level) ---- breed w/ ----> Female Charmander ---.
Breed with Female Larvitar <--- Offspring MUST be MALE Charmander <--'
Otherwise, go with Curse (breed with a MALE Slowpoke/bro/king/Turtwig/Grotle/Torterra that knows Curse).
Hone Claws(gen5) is also an alternative, without the speed. Tyranitar is slow anyway, not like a speed boost would make much difference.
I got friends with Platinum,Pearl,White,Soul Silver.
that's not the problem, but what I need to do in order to get the Dragon Dance on Larvitar?
I totaly forgot about it as egg move.