a woman in a white shirt posing for the camera

For reference I am 26M, my sister 23F on to the story, my ex-girlfriend had recently broken up with me because she caught me having sex with her mom, she was very angry, 3 days later I was feeling a bit sad and I really wanted some action. Now on to the story.This happened just this afternoon, I was in my room browsing the internet looking at porn and I got extremely horny, my step-sister calls me from downstairs saying that she was stuck in the window or something, when I got down she was wearing a short sexy skirt with no underwear, I tried pulling her out but she wouldn’t budge.Then I got the sudden urge to fuck her, I don’t know what came over me, but I undid my pant and slid my dick in her when I did she yelled “ WHAT ARE YOU DOING STEP BRO” in a sort of like a moaning voice. As soon as she yelled her mom (my stepmom) came running down the stairs to see what was wrong, she told me to get my cock out of her, and to help her out of the window. We both pulled my step sis out.Then her mom comments on how big