grundle
A noun used to define the sticky build up found underneath the scrotum.  Build up increases when the persons doesn't shower or has had hot sweaty day.
Person 1: Yo J-Kwon, take a wiff of this.
Person 2: Damn! What the hell is that on your fingers.
Person 1: I haven't showered in days, and that's some of my wicked bad grundle build up from my fat ball sack.