Noun or verb. The Rumplestilskin is a variant of the blumpkin in which a stranger initiates the blowjob while the target is on the toilet, and will continue to perform fellatio until his name is guessed. Named after the fabled trickster who would be promised a first-born child if his name could not be guessed.
John sure has been in the bathroom a long time. I hope he wasn't ambushed by a Rumplestilskin! He's a horrible guesser.