If your dog rolls over on his back, he is completely happy. Dogs usually sleep more than 16 hours a day.
If your dog's eyes are soft and radiate something gentle, you know that he feels in good hands with you. If a dog seeks physical contact, it is a sign that he is happy with his master or mistress. If he cuddles up or even lies down next to you, it indicates he feels comfortable around you. He is a real sleepyhead.