not sure i fully understand the question, but i will try to answer anyway. If you are just trying to place it on a rock to have it attached to something, I would use gel super glue. If it is on a plug, and you are trying to mount it on your rockwork, I would use and two part coral putty, or you can use super glue, but it can get tricky. As far a "dig it under the sand" if you mean can you mount it to a rock them put the rock in the sand, absolutely.