Someone who hops from cock to cock because they're insecure with themselves. They also think they need this attention, because there is something deeply troubled with them.
A girl (or guy) who's always got one hand holding a dude's cock and the other digging in his pockets. They are completely unable to sustain themselves on their own and are closer to being parasites than human beings.
Person 1: Whatever happened to that hot chick from high school?
Person 2: She realized that she couldn't do anything else useful for society so she just became a cockholder. I see her at the bar with a different dude every night, and he's always buying....