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The most disgusting porn in the world - combing all elements of repulsion to create something which will make most sane people vomit, includes:
Coprophilia, bestiality, cum shots, sadomasochism, necrophilia, midgets, old people and zankos (see definition of a zanko)
Roger bashed off to grumble porn at 5.30 - his regular daily slot.
by Dave July 14, 2003
really sick hybrid porn, especially that porn which involves not only dwarves, but shemale scatophile dwarves
I Hate You! You're Such A Grumble Porn-Star!
by Bubba July 14, 2003
a combination of the sickest, most disgusting porn

an example of grumble porn is:
a still born male siamese horse with it's head up with mother's arse being shat on, with a male old midget bum fucking it whilst spank the horse with a whip
"Haha, Jack's into Grumble Porn!"
by Dan July 13, 2003
You see your parents / grand parents / great grandparents fucking
Oh fuck - I saw my (parents / grand parents / great grandparents) making 'grumble porn'
by Dave July 14, 2003