Does a schoolgirl pin hurt?

It sure can if the girl sitting on you weights more. It also depends where she is sitting. If she sits high on your chest or on your neck its hard to breath and is very hard to get out of. Also if her knees or shins are pressing hard against your biceps it can be very painful.

It can also get painful if the girl sits on your lower ribs.

To make it more painful the girl can add bottom bouncing to the school girl pin. To do this she raises her body a little then drops with her full weight onto the man's lower ribs or stomach. It is important not to raise up too much otherwise it may give the man room to bridge or wriggle out. However, even the impact of a drop from a few centimetres/inches or so mounts up when it is repeated several times. Each drop will knock a little bit of air out of the man, weakening him further. As he weakens, the girl can raise up higher and bounce harder to increase the impact. Obviously it depends on the fitness of the man and the weight of the girl but in my case despite being fairly fit, with a 70KG/150 lbs girl I was completely helpless and unable to prevent her from bouncing on me after only 10 bounces. She continued bouncing on me higher and higher until she was squatting over me and dropping from 30cm / 1 foot up. I had no choice but to submit.

Another approach is for the girl to kneel high up on the man's chest or neck, with her calves under his shoulders. She should grab his wrists and stretch his arms high above up his head. She then traps his head between her thighs. The girl then repeatedly squeezes the man's head between her thighs, and rubs it with her thighs (this can be quite effective if the lady if wearing rough clothing like jeans). The girl can also bring her thighs together effectively smothering the man. Even if the man does roll her to the side, all she has to do is to cross her legs at the ankles and stretch them out to squeeze the man's neck or head between her thighs in a scissor hold. Although a man's upper body may be stronger than the girls, her lower body is just as strong and few men will be able to escape from a head or neck scissor hold. When he weakens she can go back to her school girl pin. The man will probably not try to escape again. This variation of the school girl pin, where the girl's calves are under the man's upper arms, rather than her knees being on top of his arms, is therefore a very difficult hold to escape from. It is also possible to use bottom bouncing in this version, it is less effective on the upper chest than the lower ribs or stomach, but the cumulative effect of the bounces will ensure that the final effect is the same.

If the girl is on top of the man in the more conventional school girl pin where she is kneeling on his biceps and pinning he wrists above his head, then there is a risk that a strong man may be able to bench press a lighter girl off. To try to prevent this the girl can push her knees out into the crook of the man's elbow, while still holding his wrists. The man then has to push against the strength of her legs rather than just her body weight alone. Most men won't me able to do that and will wear themselves out trying. It is also her painful on the man's arms.

Another approach I have seen that takes some skill is to add a grapevine on the man's arms. This can be done when the girl has the man's arms in the crook of her knee with her thighs on top and her calves underneath, and the man's arms are at right angles at his side with his hands by his waist. The girl pushes the man's arms under her feet and taps them there with her toes on the mat and her upper foot against his forearms. She then leans back, forcing his wrists down and his upper arms up. This can be very painful in the man's shoulders. It also leaves the girls hands free for further taunting.