What is a schoolgirl pin?
It is when a girl sits places a man between her hip and sits on either his face, stomach, or groin. It is commonly used in Mixed Wrestling videos and other such fem-dom practices. Normally the one giving the pin is dressed in schoolgirl attire (tight uniform, miniskirt) or skimpy lingerie/beachwear.
A school girl pin is applied by the attacker sitting on top of the chest or stomach of an opponent who is on their back, using their weight to keep the opponent immobilized. It is a natural move in a fight that winds up the ground. There is no particular attire associated with a school girl pin being applied in a mixed wrestling match or catfight, though a bikini is very common.
The girl will normally pin the man's arms down by holding his wrists. She may also kneel on his biceps, and sometimes his wrists at the same time. Alternatively she may stretch his arms out over his head, trapping his elbows with her knees. Alternatively she may kneel on his biceps and spread her knees out wide in to his elbow joints. The downside of kneeling on the arms is that a very strong man may be able to bench press her off. Another alternative is to kneel on the mat, and to trap the man's arms in the crook of her knees. Even if he does manage to get his arms free, she can usually just roll to the side and apply a scissor hold around his neck.
I believe that is is called the school girl pin simply because it is a fairly simple pin to learn and apply and it is common in school playgrounds.
Bouncing on the man's stomach or chest can help to wear him down.
Moving up to smother his face can force him to submit, although that is rather more for humiliation and fem dom than wrestling. This manouver is known as the full face pin, rather than the school girl pin.