Janāḥay is dual, representing two wings. Takannafā is a dual masculine perfect verb in Form V (tafaʿʿala): the two sides surround or flank something. The verb conveys enclosure from both sides.
Ḥifāfayhi is also dual, meaning its two edges; the attached -hi refers to the tail in context. The matching dual forms establish the spatial structure of the comparison, not simply an ornamental repetition.