noun
or skull session
1. : a training class held by an athletic coach for planning strategy and diagraming plays
hold skull practice an hour before school each morning — J.M.Blount
2.
a. : a meeting for consultation, discussion, or the interchange of ideas or information
just got through having a skull session with the county leaders — New Yorker
b. : intellectual exercise
the product of intellectuals interested in experiment, abstractions, erudite allusions and other skull practice — C.B.Taylor