He thinks he’s a cat
They say that men who grow up surrounded by women become feminine and gentle, and apparently, the same goes for dogs. This dog grew up with two cats, and he’s learned from them and adopted their ways. He doesn’t care if he’s too big for this cat apparatus, he’s going to enjoy it like his two siblings do.
Can you blame him for wanting to be like his friends? He saw the cats are doing that, and he figured it was something all animals do, because he doesn’t know any better. We all want to be included, among our friends, in our work place, and anywhere we go, and it turns out dogs are no different.