noun
waiting wrestler's sitting cushion
In sumo, the cushion placed on the dohyō for the next wrestler to sit on while waiting for their bout.
次の力士は控え布団に座って出番を待つ。
The next wrestler sits on the waiting cushion and waits for his turn.
Compound of 控え (hika-e, 'waiting, reserve') and 布団 (futon, 'cushion'). The term is specific to sumo.