This works best in shallow water where your participants can rebound off the bottom of the pool. It can be a little confusing for some particiapants so take your time when trying it... (not for us)
Using a rocking horse motion begin
When your participants get really good at it they can really move through the water. Adding in a tail with the hands when pushing the water around. For many participants who enjoy independent challenges, this is a great one. Even just for a laugh!