Mordecai's Bed is seen in numerous episodes (The Unicorn Have Got To Go, Ello Gov'ner, Do Me a Solid etc.). In Diary, it's revealed that Mordecai's bed has two mattresses, one that was supposed to Rigby's. Now that Rigby knows this, Mordecai may return it in a later episode.
Unlike Rigby's Bed, Mordecai's bed is an actual bed. It has a blue sheet and a pillow. There is an alarm clock and a lamp nearby.