Begging my step-brother to fuck my ass

POV: Your step- sister shows up out of the blue after not seeing you for a year "Listen I have a BIG favor to ask you, I need you to fuck my ass" She's found the man she wants to marry but he thinks anal is gross! She begs you to fill her ass! She needs it and cannot bear to ask a stranger for it! Wont you please be a good step-brother and full my ass?