The S Mount is an incredible control position. Many use it merely to transition to an armbar, but the possibilities go beyond that. Big Guy BJJ shows us that it is also a great spot to put extra pressure on the diaphragm.
When rolling with larger opponents, the S Mount might be the best option, because attempting to hold mount can be difficult when they have large bellies. S Mount takes the awkwardness out of the position, and puts them in a world of hurt.
Check it out, and let us know your thoughts.