One who initiates the act of fellatio; a fucking cocksucker (the kind that engages in oral sex, not an asshole, a buttknocker, a bungsnoipe, an asshaberdasher, etc.).
This term is usually used to describe faggots, but it can also be used to describe a very despicable person.
1: John wants to be a penus vacuum -- what a fucking F46607!!!
2: Osama bin Laden was such a penus vacuum; I'm so glad that the Navy Seals hosed him down!!!