T.C.B.S.
From Tolkien Gateway
T.C.B.S. is an acronym for Tea Club, Barrovian Society. J.R.R. Tolkien and his friends at King Edward's School in Birmingham met regularly at the Barrow Stores, which is where T.C.B.S. got their name. The friends continued to stay in contact with each other's literary work until 1916.