Originates from the band name Psychedelic Porn Crumpets. There are two likely definitions:
(a) Describes a pornographic or sexy crumpet; a crumpet that looks very appetizing
(b) A porn star. Crumpet referring to a sexy person (usually a woman)
(a) Hey Jerry can you pass me that porn crumpet?
(b) Mate, is that the porn crumpet from "Revenge of the Tentacles 3"?