The Therapeutic Uses of Waterbeds

Charles Hall invented the modern waterbed, but there were earlier ones used therapeutically. Mark Twain wrote about them and Elizabeth Gaskell wrote about them. They're so heavy they can weigh 900 kilos if you've got a big double or a king's. In New York leases contain a standard clause which says no waterbeds. How often do you flick your mattress? Do you mean flip it over... What other interpretation are you ... I was just trying to find out what he meant by 'flick'