Stepsister takes out all my hot cum and swallows it! She is a whore

My stepsister is a very hot woman, with huge tits and a big ass! However, I love her little mouth and she knows it. Today she was very horny, and she suggested giving me a very deep oral sex, until she got all my hot semen, and she did it! And he swallowed it all! This whore sure knows how to satisfy a man. Now, she tells me that it's a secret between her and me, and that her boyfriend, who is a cuckold, can't find out! What would you do in my place?