pound sand

verb3

1. •
   (informal) To engage in a simple, useless activity that anyone would reasonably know how to perform.
2. •
   (slang, disapproving) To go away; get lost; go to hell; to waste one's own time (with some other meaningless task) rather than waste the speaker's time with something equally irritating or pointless.

   • All you do is complain. Why don't you go pound sand up your ass and stop bothering the line staff.
3. •
   (informal) To engage in a futile activity.

   • […] Without men on the ground, we'll be pounding sand." — 2010