A person who has a lot of cock in them all the time. Like a cash register has money, a Cockregister has cock, or penis, dick, one eyed yogurt slinger, wang, tube steak, or a big fat tan juicy happy.
Taylor: "...You're a dick weed motherfucker, you fagget, Jesus!"
Chris: "Fuck you, you... COCKREGISTER!!!"
Taylor: "What the fuck does that mean?"