Crud Bud

The dirtiest, smelliest, or most pungent point on an individual's body at the time of reference, often a place of anatomical significance.. ie. belly button, arse cleft, nipple, advanced neck pimple, rotten toenail.

"I have a strange tingling in my crud bud.."

or

"Look buddy, i'm telling you this for your own good.. you've gotta do something about that crud bud of yours.."