What is passing the guard, and why would I want to do so?
The Guard is one of the fundamental postitions of Brazilian Jiu-Jitsu, and Mixed Martial Arts. The guard is an effective neutral position in grappling. Even though one person has their back on the ground, because they are controlling the man on top by wrapping them inside their legs, keeping them close, the person on top cannot acheive the distance neccessary to wind up and punch the man on the bottom. In addition, the person on top is vulnerable to a variety of submission techniques, such as chokes or armbars. Hence, it is to the advantage of the top person to break free from the leg grasp of the bottom person, a concept of grappling known as passing the guard.
How to pass the guard(Standing Method):
While placing both hands on your opponent's biceps, stand up inside his guard. Then, grab his belt with one of your hands, and use the elbow of that arm to push on the inside of his thigh. The combination of these two actions should break open his or her guard. Now, using the hand that was not holding the belt, reach around the opponent's leg (the leg nearer the arm being used) at the thigh, and pull it upward. With the hand of this arm, reach all the way to the opponent's collar on the opposite side, and grab it. Now, lean forward, "stacking" the legs of the opponent toward their head. By "stacking" their legs, you should then be able to clear your own head from the grasp of their legs and move around the side, pressing your own chest into theirs, achieving a dominant side-mount position.
Advantages and disadvantages of this method:
When one begins standing inside the opponents guard, they leave themselves vulnerable to a variety of sweeps, such as the ankle-grab sweep, which is simply the fighter on the bottom grabbing the ankles and pulling forward, causing the man standing to fall on his buttocks. The standing fighter is also opening themself to submission techniques, such as the triangle choke or the armbar. The advantage of standing up to pass the guard is that it moves the head away from the opponent, as opposed to passing from a sitting position, where the head is moved closer to the opponent. Since one's arms are occupied while passing the guard, in a real fight it is a great advantage to not have one's head close to the opponent, even while they are lying on the ground. Otherwise, the enemy could respond to your pass attempt by punching you in the face, which would hurt and be a bad thing.