Sister-in-law says knock her up and keep your mouth shut

You walk into a hotel room expecting to see that you hired for the evening and are shocked to see it is your sister-in-law. At first she is a bit upset and says she has you over a barrel and she knows you have already knocked up your wife several times and now she wants the same. She tells you that she wants you to give her your hot seed so she can get pregnant as well. The deal is, you get a freebie fuck and she gets knocked up and both of you keep your mouths shut. She then starts to pose and show all the positions that she would like to fuck you in and puffs her belly out to show you how hot she will look when you get her pregnant and talks about how big her tits will get with milk. She wants to get knocked up and she knows you have always wanted to fuck her so what do you say? Get laid and keep a dirty secret with your sister-in-law, you know you want to.