Is my puppy showing aggression or submission to my son?

I have a 6 month old bulldog puppy (Hoss) , and a 20 month old son. Hoss is quickly getting bigger than “E”, and they wrestle all. the. time.

Sometimes, Hoss will seem to run right through him, knocking the baby over, then come back and mouth the baby’s hands (always very gently – he’s never left a mark). If “E” manages to stand up, Hoss will roll over onto his back and stay there until “E” tackles him again.

I’ve read that in young bulldogs “dominance play” should be discouraged and should be curbed as soon as possible. I don’t know much about dog behaviour, so I want to make sure that everything’s okay.

Thanks!