The 5 best dog harnesses for a Cockapoo sized dog reviewed. Get a stable harness for comfort and to help train a #cockapoo puppy! Taking a Cockapoo for a walk is an exciting whirlwind of energy, excited sniffing, and even a littleleash pulling. Even well-trained Cockapoo puppies and dogs are packed to the brim with vibrant energy. They love to run around, explore, sniff, and play.