bottoms up

On either side the deck, against the rail and bottoms up, were lashed a number of small boats.

Well, why the Hell didn't you say something before—good Heavens, it's been a long time between drinks—bottoms up.

Ahead, a row of bark and dugout canoes lay bottoms up on a dirt embankment.

Another way is to put both your slippers by your bedside, bottoms up, before retiring for the night.