Back in 1949 while attending Northeast High School in Philadelphia, Pennsylvania I was taking an industrial arts course in wood patternmaking. In our assignments we constructed small wooden patterns and molded them using lead using the contents of a large bin of dampened sand. The typical pattern was made of two halves and were separately mounted within the Cope and Drag within a metal framework. The most important action in securing the pattern within the Cope/Drag frame was filling the area around the pattern by pounding the sand skillfully and properly. There was more to this operation that I have covered but I have now gone far enough to get to the subject.
One day after school, while playing one of the many street games we engaged in I engaged in a mild altercation with one of my buddies and in response to something he said I barked out
"Aw, go pound sand up your ass!" For some reason this broke down the house with laughter from all present. I had to explain that the phrase simply leaped out of my mouth unplanned. However, the phrase caught on and was used more and more locally. I cannot say that I was it's source but nonetheless it was original by me.