My dog CoCo acts quite aggressive at times. She is around 16 weeks old and has had 6 weeks of puppy basic training....but now refuses to do these things as requested. That is not my complaint though. She gets pretty rough by jumping at me with her front two legs while barking loudly and biting/nipping at my hands, my arm, or my sleeves for no reason. Does anyone know why she is acting this way? She doesn't act this way to my husband though.