when one has failed to shake off properly after emptying their bladder; a piss stain is left that soaks its way through to the trouser front leaving a circular stain.
" mate look over there your dads got a richy b!"
" she said it was the biggest she'd ever seen then got up and left. i couldn't believe it, i had a richy b the size of a golf ball."
" remember to always have an extra couple of shakes, don't wanna go around with a richy b."