Dear parents... Well, I first needed to get the dragon into my "faction", because theyr default "faction" makes all dragons attack everyone ^^. Then I just had to sit (mod needed...) in front of the dragon. There's one thing, that annoys me. You can't really speak to any dragon except 3. Most of the dragons in the game don't have a dialog, or speaking sounds. I think, bethesda should improove that (ooooooor a modder...).