Let's take a look at the calf slicer / compression lock. In this technique, we'll use the forearm/wrist as a wedge inside our opponents upper leg. The placement of the wedge and the force applied on the levers act to hyper-flex the knee joint, as well as add nerve pressure to the leg muscles.

This is particularly useful when our opponent is defending against the kneebar by triangling off their legs and holding tight, but it also can be used from several other leglock positions and can be a valuable counter to have.