An Old Bottom wants to be loved -Obsessive sex with a younger doggy

Story :  "If you're the one to put inside... Then I'm okay with it." Sakai, a gay man who used to be a teacher, saves Ao, a handsome college student, from getting entangled with a stranger. Ao asks him to return the favor and they end up having a drink at a bar. While Ao shows his youthfulness, Sakai starts thinking about being in bed with him. And when he starts his imagination, Ao invites him out...! Sakai takes the lead by saying "Sorry it's an old man's asshole, but you can fuck it hard as hard as you want." However, when they start having sex, Ao pounds Sakai's prostate hard and takes control and...!?