It is placed on a small zabuton (traditional Japanese cushions used to sit on the floor)-like table, and it sounds like 'poku poku' when it is beaten with a plectrum whose top is wrapped in cloth.
小さな座布団状の台の上に置かれ、先端を布で巻いたバチで叩くと、「ぽくぽく」という感じの音が鳴る。