Go wide with your inside hand, but not down. Then as he start to except it, start bringing your hand back to its usually place. Until he excepts your hand. Also lots of forward motion. Don't let him suck be hind your leg. As they except contact and carry themselves they start to slow down. Don't let him. Encourage him as he is doing the right thing, but keep him at the same even tempo and push him forward. Contact and connection is back to front, so you need the momentum to be able for him to except the contact.