Guard Escape (Elbow Drive) - Brazilian Jiu-Jitsu Techniques

You are inside your opponents guard.

Grab hold of your opponents belt with your fingers underneath.

Now drive your elbows down into your opponents thighs. This will cause immense pain and should cause your opponent to uncross their feet. It may even make your opponent feel slightly faint if you manage to apply enough pressure to the main artery in their legs.