In the first video below former UFC Heavyweight Champion Frank Mir goes over a sweep from the Half Guard that he calls the Superman. This is a good option when your opponent has tight Head & Arm control and you are having a problem getting the underhook.
In the second video Frank goes over regaining good position if your opponent bases out to prevent himself from being swept. When this happens the path is wide open to get the underhook. Looks like a really nice 1, 2 punch.
