If you can trap an head and arm between your knees, you will immediately be in to attack the upper with submissions. The of Jiu jitsu is always to control greater strength and aggression with lesser strength and aggression. There are different ways to express this ideal – but one of the very best is to match the strength of your against an opponents arms. This is a battle you can consistently win even against much stronger opponents. A simple and extremely effective way to do this is to clamp your opponents head and one arm between your knees while taking an angle. This opens the door to arm bars, triangles, kimuras, omo plata – even locks if you know what you're doing. It immediately a passive or neutral bottom position into a highly advantageous one – look to get there as often as you can!