While sitting/kneeling, place your hand, with your palm facing upwards, between your knees. Have a treat in your other hand and lure your pup towards you so that their chin rests on your hand. Say “Good” and give them the treat. Throw a treat away from you to move them away. Repeat. When they can do this consistently, repeat as above but without the treat in your lure hand. Say “Chin” as their chin rests on your hand before giving them a treat. Repeat.