Green’s Dictionary of Slang

(drugs) the act of smoking heroin.

2000		J.J. Connolly Layer Cake 161: ‘When the money turned up he had a little boot.’ ‘A chase?’ ‘Yeah.’.
2012		(con. 1980s) I. Welsh Skagboys 250: Ah’ve been clean since we hit London, apart fae the odd chase and some speed.