Right, we currently have four dogs. The second youngest one, Poppy, used to sit on the other, older two bitches. Now we have a younger pup, a boy called Buster, Poppy no longer sits on the other two girls, but Buster sits on all three of the girls. Both Poppy and Buster would choose to sit mostly on the 'matriach', Indi, the oldest of my girls and I suppose she is top bitch.
Is it some sort of appeasement/alliance thing?