The action of hijacking / theiving / obtaining a penis to ride or pump in a sexual manner.
Rob is a cockjacker as last night he took advantage of Frank
by Denzel Large December 03, 2007
1 more definition
Another terminology for hands ( most likely women's hands ) or anything you can jack on a cock.
Don't touch me with your cock jackers
by Anoble0130 February 01, 2011