Lucy was AWFUL about doing stuff like that when I got Rebel. (She's a 10 pounder too and Rebel weighs right at 5 lbs at 1 yr)
Lucy used to chase him under my wrought iron coffee table and he'd bump his head EVERY time.
I finally started telling Lucy "no" when she did it and putting her in the crate for a few minutes. She absolute hated that and now she doesn't do it anymore.
Also, Rebel gives her FITS now
