Bocephus went through this phase too, he's eight months now and it has gotten so much better. I think they are still learning boundaries (although I am no expert). He still will occasionally get real mouthy when he's excited or wants extra attention. I try to be consistent with telling him"Gentle" and if he gets too worked up, I will out him on his back and place my hands on his belly until he clams down. I don't hold him down, I just make sure he knows that I am dominant to him.
I am sure others will be along as well, it's a completely normal phase.