Darīr is connected to d-r-r (د ر ر) and denotes rapid, sustained movement. It functions here as a descriptive adjective of the horse, not a past-tense verb. Khudhrūf names the spinning toy activated by a string or by a child's motion, highlighting rotation and repeated momentum.
Amarrahu conveys setting the toy into forceful motion; tatābuʿ means successive, uninterrupted action. The child's two hands matter because the toy's movement is maintained by repeated impulses.
The prior verse showed how the horse shakes or displaces a rider. This one develops the continuity and repetition of its motion through a new, concrete comparison.