Arabic to English Art/Literary Poetry & Literature

قال وهو يمطّ شفتيه: بالله عليك، هل يختلفُ ذيله عن ذيول الحمير؟ وما هو شكل أذنيه؟ وكيف يمكن العثور عليه وفقًا لهذه المواصفات

Hi everyone,

I'm translating a Palestinian young adult novel. In this section, the narrator is suggesting to his friend, who has lost his donkey, to put an ad in the local paper describing the donkey, in case anyone has seen it. The friend doesn't seem keen on the idea.

I'm wondering what the significance of this phrase is: is it meant to imply that his friend is annoyed, or angry? Is it similar to the English phrase "pressed his lips together", used to convey disapproval?

Many thanks!
Anam