Cain has generally been quite submissive when meeting people and other dogs. I don't think it is anything to be too worried about because I think its his way to say hello. When he meets people, he rolls onto her back for a belly rub. When meeting other dogs he will bend to the ground and approach and than either roll on his back or sniff them. Depends on the dogs size. He's good at meeting dogs his size but quite a bit more submissive with larger dogs.
Is this anything to worry about or is it just the way he rolls?