mary:     you've left a bit of potato in that pan  jacky:    oh god mary, you're such a backseat washer upper
when someone is standing behind you as you are washing up, pointing out all the dirty marks you have left on the pot's!!
"mary:     you've left a bit of potato in that pan  jacky:    oh god mary, you're such a backseat washer upper" What is the definition of "backseat washer upper"?