我的女朋友让我帮她做作业，我走进她的房间，我受不了操她的冲动，所以我在她体内射精

She asks me to help her with homework, that's why I go into her room and since I can't stand the urge to fuck her, and there's no one else there, I decide to lift her skirt and fuck her, I came in her after having sex.