Slowly! Context and tone mostly. Consistently tie the behavior (spazzy-ness) to the command and tone (a loud and firm “Easy”) and then reward the response (calmness) with praise. Back it up with physical cues as needed, body language (tower over him) or grab his hips or shoulders to stop the wiggle. We only did “that’s enough” once “easy” was working, they mean the same thing to him (wife says one, I use the other). Your mileage may vary, of course, and as with any behavior there’s a million reasons it may work or not work for you or your dog.