Tell him the only way you'll let him go is if he cums in you

From Create Your Own Story

He doesn't know what's going on, and he still doesn't seem totally comfortable, but he doesn't want to pass up the chance to have sex with a hot girl, and he doesn't have much choice. He starts pumping his cock into your pussy. He starts fucking you harder and faster while the kids around look on in horror. Just as you both start to cum at the same time, with waves of pleasure emanating from your pussy and gushes of semen filling you, a teacher comes in.