His mother promises to fuck him if he passes the next exam

An important test is coming that will influence whether this guy can get the degree or not, so he needs as much help as possible. Her mother offers to tutor and help her study, but the son surprises her by sticking her cock in front of her. She tells him that if she does a blow job, she can concentrate better to study, to which the slut responds "well, but only once." Another day the mother promises to fuck him if he approves, which leads to the son trying hard thinking about the prize he will have. And when he returns from the exam with the pass, he fucks her in a bestial way looking at the piece of ass that the mother has.