hit the sack

hit the sack (http://definr.com/hit the sack)

     v : go to bed in order to sleep; "I usually turn in at
         midnight"; "He turns out at the crack of dawn" [syn: {go
         to bed}, turn in, crawl in, kip down, hit the hay,
          get into bed, sack out, go to sleep, retire]
         [ant: get up, get up]