Green’s Dictionary of Slang

a single curled lock of back hair, worn pulled forwards over the left shoulder.

[1898		Daily Tel. 21 Jan. in Ware (1909) 251/1: Miss Spong’s fair hair is all pushed into a gold net, save for one long tire-bouchon hanging over the left shoulder].
1909		J. Ware Passing Eng. of the Victorian Era 251/1: Tubbichon (Peoples’, ’60’s). Corruption of tire-buchon (corkscrew) which was the Paris argot in the ’60’s for the long solitary ringlet of a portion of the back hair worn in front of the left shoulder, a fashion created by the Empress Eugenie, and accepted in Trondou by the middle classes immediately after that lady visited London (1855), when for a time everything French was very popular.