I would sick my Najasaurus on Gregorio, then Disco my Najasaurus, while running Whispering on cooldown.
Gregorio is a red brigand that spawns at a farmhouse near the Ranger Huts outside of Skara Brae. He's immune to damage unless you're on a specific quest, he himself deals virtually no damage (especially when Disarmed of his Pitchfork), and he's very easy to land hits on, so he's the best for training almost all Magic skills (except Discord) on for pets. He's also the best for Anatomy gains, as well as LJ gains for players. With a pet, just be careful of having your karma tanked by the Peasants, Cats and Dogs walking into your pet's AoE.