Wiktionary
pound sand
vb. 1 (context idiomatic English) To engage in a futile activity. 2 (context idiomatic dismissal English) To go away; get lost; go to hell.
Usage examples of "pound sand".
Besides, for all I know, you've already got a career in politics and my mama didn't raise any kids who like to pound sand down rat-holes.
Mind you, when I bought them, they were too ignorant to pound sand and I don’.
Mind you, when I bought them, they were too ignorant to pound sand and I don't think either one had ever touched money at any time.
He'd have laughed in your face, or spat in your eye, or told you to pound sand - whatever you like.