Faye 4lb Chi/Yorkie and Morrison 45lb Lab/Beagle/Basset absolutely love each other. Osha and Lacey really don't play. But Morrison is more than happy to have a tiny playmate. If you watch he is very careful (though he sounds vicious) not to be rough he actually hardly touches her.
And the leash is not tied to anything. It's just on her for house training purposes.
Faye And Morrison Playing - YouTube
Morrison and Faye Play - YouTube
Oh! And the barking is not Faye. It is actually my Pomeranian "Honey".