When my dog is excited and wants to play she always bites and uses her mouth, mainly biting on my arms. She also sometimes when we are playing will jump towards my face with her mouth open so she gets me with her teeth. Anytime we play around she always uses her teeth. Another weird thing she does; Sometimes when my girlfriend and I hug in front of her or we play fight, I tickle her, or anything of that sort she will start barking and growling at us or me but still has her tail wagging. She never gets aggressive and tries to attack one of us but I really want to know why she does that every time. I know she isn't going to hurt me but I feel like she is really trying to protect her "mom." When we first adopted her she was afraid of squeaky toys but now all she does is squeak the toys to try and get us to play with her. She was also afraid of the bathroom and would not set foot in it or get close, but now when we shower she will lay by the door waiting for us to get out and has no problem walking in the bathroom.. She is also very afraid of any cage. If I go near her cage she lowers her back and starts to run away. And when she does go in the cage she pants so much and if we are gone for an hour or so her paws and her chest will be soaked, it is so strange.
We adopted her when she was 2 so I wish I knew how she grew up and what she was taught as a puppy and what happened to her.