The Brief: Cunch is slang for "country." In slang, it means an urban district where an individual goes to sell drugs.
“Cunch” means country, as defined by Urban Dictionary. More specifically, it refers to an urban district. “To go cunch” means to go to a far away region to sell drugs.
A November 2017 Vice article on “going country” discussed “cunch” and the growing number of young people employed by city gangs to sell drugs in towns across the UK.