Grundle is another word for chad: the region between the balls and the arse-hole; can be an erogenous zone for some.

Girl: I was fingering that part between his balls and his arse and there was shit there.
Everyone listening remained silent but later laughed among themselves:
'Eww! He had a shitty chad.'

When you measure your dick, you don't start at the arse-hole and include the chad; you risk getting shit on your measuring tape.
Q: What on earth is a grundle?
A: You know, the chad, the part between balls and arse.
by Chane. March 28, 2020
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the art of pulling down your pants and smashing your testicles and anus down on the head of a passed out human repeatedly.
Luke puked in the frying pan before passing out, so Nate gave him a grundle
by weiser May 2, 2005
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A protuberous underside. Particularly on an adorable animal.
My cat has the wobbliest grundle.
by Abiy0y0 February 26, 2017
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The little pieces of pooh and underwear lint that get caught in the hair around your anus.
My Grundles were making me itchy, so I picked them off.
by Bud Green February 7, 2004
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a breakfast sandwich usually consisting of sausage, egg (at least what the government tells us is egg) and cheese on a bagle or english muffin
oh snap! today is grundle day! I'm getting breakfast
by Rimmer April 7, 2005
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1. The small particulate matter or shake that remains in a stash of marijuana once all of the larger "dank nuggets" are gone.
2. (In male human anatomy) the area between the scrotum or ball sack and anus or butt hole respectively. Also commonly referred to as the taint.
1. Dood grundle is like smoking dust.
2. When I wrecked my bike the seat hit me right in the grundle.
by Sea of turds January 5, 2011
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