OK so here's my question. I'm trying to figure out if there is a way to put a box or whatever into the dunes. I tried the save and quit method but it didn't work. I'm trying to merge the box into the sand just outside the grid, so i think that's whats causing problems. Just the bottom part needs to go in. Does anyone know how to do this? (and if there's a post somewhere telling how to do this just link the post and i'll ask a mod to lock this. I looked but I couldnt find anything.) EDIT: I FOUND OUT HOW TO DO IT! I'm still working out the flaws but I'll put a tutorial up shortly.
It might be that you can't becuase of the Sandbox glitch. Once Bungie says that they have fixed it, try geo-merging again.
I was actually just trying to figure out how to do this myself. I finally got it to work by doing something similar to the door method. All you do is surround your object on 4 sides, leaving just a small bit of space for you to grab the object with. Then, put a leveled double box on top of/interlocked with the object you want to push into the ground. Finally, just double-tap A on the object and it sinks perfectly into the ground after it spasms a bit.