Big Stick Ideology?

Took Fossey and her neighbour, Poppy, a sweet little Border Collie, out for walkies this morning. They were well behaved and Fossey's jealousy seemed to have subsided ( she was guarding me the whole way round when we all went out y'day evening! ) until Poppy found this big stick and hoped I'd throw it for her. I tried, but Fossey grabbed it and altho she'll retrieve things, she won't hand them over. Poppy moved on, but Fossey insisted on hanging around me and caught me across the back of the legs a few times before she got bored of it!