Я помогаю моей застенчивой сводной сестре с ее домашним заданием, и в конечном итоге трахаю ее жестко, пока я не кончу

My stepsister is a very judicious girl, she always does her homework and makes sure not to miss any class. She is obedient and does all the tasks, I assign her some tasks and I end up fucking her hard.