has been backwashing

• present perfect progressive

  present perfect progressive

  Used to describe an action that began in the past, has continued continuously, and is still in progress.

  of backwash (3rd person singular).
  backwash

  noun

  water thrown backward by the motion of oars, propellers, paddle wheels, etc.

More Suggestions

• hand-washing
• queer-bashing
• spine-bashing