(nark, narking, to nark/be narked)
A very general termusually referring to or meaning: To steal/tattle on/lurk/creep on/fail/vomit/et cetera.
Again, this term is very universal and can be used for or applied to more than just the above.
Person K: Dude, I just totally narked some Sophomores!
Person M: Oh, the usual?