A pen or pencil that has been chewed/sucked on repeatedly.
Sometimes italicized when written.
P1: Are you going to write for the school journal again this week?
P2: Yeah. Writing under a pseudonym makes me feel like I have the freedom to honestly express myself.
P1: Are you going to use the same nom de plume as last time?
P2: Nah. It doesn't even write anymore. There's as much spit as ink in that thing.
P1: Ugh, that's some epic nomming.
P1: Can I borrow your pen?
P2: What happened to all of yours?
P1: My girlfriend's terrier got into my bag last night and went all nom de plume on them while we were watching Heroes.
P2: I think you mean "nom des plumes?"
P1: Whatever, just give me a pen.