Grundlemuffin 

The placing of one's fist into one's grundle and letting it bake there for a minute, then removing it and punching another person across the face with it.

Bitch, if you don't shut your mouth, you're gonna get a big ol' grundlemuffin!

Grundlemuffin by Head Chef McC December 21, 2006

Gargantuous Grundle Muffin 

The point at which a vagina becomes crunchy.

Man when I was f**king your mother last night she developed a gargantuous grundle muffin.

Gargantuous Grundle Muffin by qwerkyduckbutter March 26, 2013

grundle muffin 

A delicious mix of excavated nuts, mixed with grundle juice (see prior reference)and nether-yeast, baked overnight after a 5 hour tequila fu*k. Serve warm with coffee.

Honey, bring me some grundle muffin and some aspirin.

grundle muffin by Viva La Grundle January 24, 2006