This is another wrestling technique that is used often from the Russian 2-1 tie up. One of my team mates, Victor Raphael, used to smash a lot of shoulders back in high school with this move, even dislocated an opponent’s shoulder!
So be cautious when using this move. I take it easy when demonstrating this, but in real practice you would slam all your weight down on his shoulder as you collapse to the mat.
The submission bonus here is that you can get an arm lock on the mat if you table his wrist on your far thigh and use your body to apply pressure to his elbow. If not, you can score a back take here as well.