This call is no longer used at any level.
At C4, there is a similar call named Turn Over, which is a Cast Off 3/4 & Slither. Turn Over is nice smooth call and is often used.
Turn Over is usually called from Parallel Waves, but is also interesting from Back-to-Back or Inverted Lines (Cast Off 3/4, Centers Half Sashay).
Grand Turn Over (from Columns) is a Cast Off 3/4 then Center 6 (Grand) Slither.
I recall that we also used to do <anything> Over, which meant do the <anything> call then Slither.
