Our 4 year old Boston, Wally, picks on our new puppy, Roxy, constantly. He doesn’t seem to just let her be at all. She does participate but will also want to do her own thing for a moment and he just won’t leave her alone. She ends up being so over-stimulated and exhausted from fighting him off. He also tries to hump her quite a bit. How can we get him to be less aggressive toward the puppy?