The washer is ancient. Needs a kick when it unbalances and threatens to march out the door.
Right now it's banging against the wall, rattling like there's something loose inside, but it's not even going.
Sam's got Dean bent over it.
A chunk of plaster breaks off the wall as Sam gives one final thrust and comes inside his brother.
"I meant while it was running," Dean says when he catches his breath.
"Be specific." Sam's reason fails when Dean says shit like 'fuck me over the washer'.