Green’s Dictionary of Slang

cock (a Broseley) v.²

to smoke.

1846		G.W.M. Reynolds Mysteries of London I 399: The king had in the meantime amused himself with what, in bis own lingo, he termed ‘cocking a broseley’* [note] *Smoking a pipe.
1864, 1870		Hotten Sl. Dict. 103: COCK, a smoking term; ‘cocking a Brosely,’ i.e., smoking a pipe. Brosely in Staffordshire is famous for ‘churchwardens.’.
1890–1904		Farmer & Henley Sl. and Its Analogues.