rubber room
n.— «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.» —“Slumping Watson Is ‘Discouraged’” by Thomas Boswell in Augusta, Georgia Washington Post Apr. 11, 1984. (source: Double-Tongued Dictionary)
Further reading
Katie in Everett, Washington, is curious about the expression If ifs and ands were pots and pans, there’d be no need for tinkers. What is a tinker? She heard this phrase on the television series The Gilded Age, in response to a character who...