Playful Cassy With Spooky

Spooky, our dog used to be the alpha dog in our family since she really has this territorial attitude in her. But ever since Cassy was born, she has learned to accept that she comes after Cassy. We didn't have problem ever since with Mojo, our other dog, as he has always accepted to be the second or third (whichever he's just fine).
Now, Spook is too gentle and really get along with Cassy well. Cassy calls her popo as it's easier for her. We always teach her to be gentle with them but she tries to be rough sometimes. I am just glad that the dogs don't mind, still I watch them closely.