In learning how to be "Top Dogs" in our house, my husband and I had to learn to hold Rascal (our 7 month old Lab mix) down while playing (gently pushing down on Rascal's shoulders while wrestling on the ground), holding a stare until he looks away, and just general control over any situation. If he's playing too hard, or chasing one of the cats, a very firm and loud NO! and LEAVE IT! usually takes care of the issue, but if it doesn't, into his room he goes, removing him from the fun and the pack for a while. It's working out well for us - I hope you can use some of this. Good luck!