A person's metaphoric wang, the size of which being related to his apparent devotion to the environment via principles, purchases, lame t-shirts and bumper stickers, etc. "Green" comes from the color commonly associated with environmentalism, and "peen" is short for penis. Duh.
While Ryan greatly enlarged his greenpeen by purchasing a Prius, Sean's Highlander Hybrid provided a decent enlargement while also allowing him to keep his dignity.
A superhero made up by Albert/Flamingo as a joke
his superpower would be to turn inti anyting as long as hit editor is not feeling lazy or, to pull out a gun and start to shoot the target.