Pogo plunger.
https://s3-us-west-1.amazonaws.com/h...go_plunger.jpg
Previously:
https://www.homemadetools.net/forum/...452#post142727
https://www.homemadetools.net/forum/...776#post148200
https://www.homemadetools.net/forum/...432#post131630
https://www.homemadetools.net/forum/...373#post127046