[Backlash by Aaron Allston][1]. It is indeed a Star Wars book.

[![Backlash][2]][2]

>At its summit, he offered the note to Kaminne and Tasander. They and some of the subchiefs gathered around could read, and news of the note’s contents spread throughout the camp.<br/><br/>
Kaminne pondered. “What’s an elegant way to say No, and we hope you die in misery?”<br/><br/>
Tasander shrugged. “My father used to say, May the stinging insects of a thousand worlds seek out your moist places.”


  [1]: http://www.isfdb.org/cgi-bin/title.cgi?1074313
  [2]: https://i.sstatic.net/2Cpiwm.jpg