"Sherknockle-boxed" is a past tense street word used in South Yorkshire (UK).
Sherknockling involes sexual intercourse in "all" area's of the partners body. Touching, Kisses, oral, and other sexual fantasy's are played out by mostly one lover, while the other lover takes it with passion!
Once the scene is over, the parter that took it with passion has now been Sherknockle-boxed.
Here's shiny metal boxes for you urban dictionary; go fuck yourself, you piece of goddam motherfucking shit fuck you, fuck you, go to hell, fuck you, fuck your whole goddam motherfucking life