Hello, I have a 15 year old female cat that is still pretty active, so I decided to get a kitten. It worked out fine at first, but now the kitten is starting to annoy her with his playfulness. I give him lots of playtime but the moment she comes around, he starts chasing her tail and jumping on her, she hisses and swats at him but he's relentless, he sees it as play! Please help! What can I do to make him back off a little!?