I have the most wonderful 3 1/2 month Pembroke (got her at 8 weeks) and I can't figure out if she's submissive or just loves tummy rubs.  She has always loved running up to people and dogs (no matter how big) when we are out on our twice daily walks and bounces around on the dogs, tries to jump up to bog dog's noses, etc. but eventually she always ends up on her back.  Especially with people, she just flops over right away and lies there smiling at them.  I thought maybe since she gets so much more coochy-cooing when she shows her tummy she just does it for more attention?  What do you think?  Is this submissive behavior?  Or just a dog who knows she has an adorable tummy?