Initially a nickname given to a younger crew member, the term has grown from strength to strength due to its increase in use.
The term describes a person who, either wants/needs/(is hungry for!) to take illegal substances, and due to this hunger,they become obsessed and attached to many aspects of the drug such as people,raves,staying over at peoples houses for extended lengths of time etc!
It is overall a joking, yet mildy undermeaning term.
"Who was that on the phone?"
"Oh it Was some hungry hippos!"
"Buttery Nipples?! I thought they were saying Hungry Hippos!"