There have been a few "eureka" moments for me when it comes to the sitting guard. One was while watching an instructional DVD from Stephan Kesting. Another one came while watching a recent competition between Cobrinha and Rafa. But the one that is still fresh happened during the seminar by Prof Otavio Sousa just a few weeks ago here at Gracie Barra Seattle.
BJJ Scout explains why my "eurkea" reaction may be fairly common in another great analysis of a great jiu-jitsu technique.