Phoebe is on the small side, the trainer I worked with fitted her with a puppy prong collar. She really doesn't need it any more but it was incredibly useful when we needed it. She now understands "easy" and no longer pulls my arm off when we walk, but before she understood easy...walking was a nightmare without the prong.
Jan, Seamus, Gracie, Phoebe & Eliza Doolittle