Green’s Dictionary of Slang

(drugs) to smuggle or hide drugs by placing them in the rectum, vagina or mouth.

1993		T. Jones Pugilist at Rest 70: I begged Thorazine from the guys who used to cheek it and then spit it out after meds were issued.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 41/1: cheek v. to hide contraband by placing it firmly between the cheeks of the buttocks, rather than inserting the contraband into the rectal or vaginal passage.
2019		D. Winslow Border [ebook] Then another guard runs a gloved finger inside their mouths to make sure that they haven’t ‘cheeked’ anything.