2 Part Technique - Sometimes, the underhook isn't the answer; it may even be your demise. For example, while stuck playing Half Guard (aka "Quarter Guard" via 10thPJJ), obtaining underhooks can leave your opponent with opportunities for attacking your arms. Instead, look to alleviate the pressure from top by rocking up onto your shoulder, then you will have the room necessary to escape further. This method of escape may not necessarily get you out of every bad position, but it certainly can buy you the time and space to think about a better means of evading your opponent's advance. Before giving up, try getting up onto your side.