It is sort of a tough call. A few times Commodus has meowed like he may be a bit scared, and Max has backed off, or I've made him back off. But then Commodus will go right back to trying to play with him, so I don't think he's getting hurt or anything. I'm giving them their space for the most part to let them work it out on their own. It's strange how BIG Max looks all of a sudden - and he's only 4 months old!!