My 4 y/o Weim still mouths my arm when he wants to play or go for walks. I just let him do it until he chomps too hard. He tends to know when he does though and before I even say anything he lets go, lays down, and crawls a little closer as though to say "I'm sorry." I know it isn't good for him to mouth but he doesn't really come in contact with other people like that without being on a leash. He also likes to bring clothes, blankets, pillows, shoes, and food bowls. I'm guessing for attention. He's the oldest puppy I've ever had.