Trinity St. Clair & Tommy Gunn in Naughty Book Worms
Prof. Gunn suspects that Trinity cheated on her test, so he asks to see her after class. When she arrives, he compares her exam to that of her classmate's, which are identical, and asks her to explain. All she says is that she needs to pass the course and that she wants to work it out in another way. When Professor Gunn asks how, she doesn't tell him ... she shows him, by getting on her knees and sucking his cock. She passes with flying cum -- to her chin.