(This was originally filmed as a custom video and the name Tyler is used throughout) You step sister Fiona comes over to talk to you one day - her and her husband have been trying to conceive for a while now but they haven't been having any luck, and she's getting really frustrated. She vents to you for a while about how much she wants to get pregnant, before you jokingly suggest that if it's not working with her husband, maybe you could help her out and get her pregnant... She laughs it off at first but then seems to consider it, and then suddenly, to your surprise she's shyly stripping her clothes off and getting down on her knees to take out your cock! She makes you promise that you won't tell anyone about this, especially her husband, and thanks you for being such a helpful brother as she sucks your cock before riding you on the couch! She then asks you to fuck her in missionary so that when you cum it will go deep inside her and make her pregnant, but while you're doing this, her husband calls her! She answers the phone and talks to him while you keep fucking her, trying to stifle her moans and telling him that she's visiting her brother and she'll be home soon. After she hangs up she cums hard on your cock, then begs you to shoot your load inside her so she can have your babies!