A piece toilet paper or shit tanglel-rolled with butt hairs. Usually discovered when crack scrubbing in the shower or when something strange drifts in the bathtub around your knees. If left unattended, they dangle and rub and build up to a knoted ball which eventually pulls the hairs out.
"Joe is such a slob, I just saw an eight-day combo nugget rolled out of his pants leg."
"I bet her nuggets clang like windchimes when she squats."
Use wet wipes if you have the runs or you'll start a nugget farm.
"Do Not go down on that unless you want to floss with nugget strings."