What is Cock Barnacle?
1.
(1)An ever-present, overly persistent and/or unwanted suitor or friend of a male. (2)A stalker.
man 1: Who's that fat chick that keeps hanging around you?
man 2: Some fucking cock barnacle that won't leave me alone.
man 3: Hey, man are we hanging tonight or what?
man 4: Relax dude! We aren't married. Why you gotta be such a damn cock barnacle?
See
2.
One who is an unending annoyance to others in the worst way at the worst time.
"My little brother managed to volunteer himself as my escort to my girlfriends house. I swear until my mom gets a babysitter he will continue to be a total cock barnacle.