Haha, they give the expression "cuddle bums" a whole new meaning!
"He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours,
faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion." ~ Unknown
I guess they never truly get over being little new born pups when they are still with there litter mates and mom they all sleep on top of each other then so why not when they get a little older. To them it is the most comfortable place in the house,