rubber room
n.β Β«Once, Watson boasted that he played golf in his own private “rubber room:” a state of concentration and confidence so deep that the perils of the course and his own psyche could not reach him.Β» ββSlumping Watson Is βDiscouragedβ” by Thomas Boswell in Augusta, Georgia Washington Post Apr. 11, 1984. (source: Double-Tongued Dictionary)