A Perfect Storm

She's trembling. Even though its awkward, she asks if you'll hold her, just while the worst of the storm passes. You eventually get her to calm down, and the thunder seems to get a bit softer. You both start reminscing about all the great times you had together growing up, sharing lots of stories and memories together. Your sister is in a top that is a bit too small and her cleavage is distracting you. You try to focus on the story she's telling but you can't help it, you get turned on. She notices your boner and confronts you. At first, she laughs it off and says it's normal for a man to get turned on by a woman in his bed. It's not like you're attracted to your sister... right? Tensions rise. You can feel that something is about to happen, there's an electricity in the air. One thing leads to another and before you know it, her hand is on your cock, stroking you. You both play it off as if you're just playing around and that this won't last long, you're bound to lose your boner! Right? Right?? You don't. She gives you a blowjob. The attraction is undeniable. You've always had a deep connection with your sister. She takes off her clothes and starts to touch herself, you can hear how incredibly wet her pussy is for you. You both work up the courage to try putting your cock inside of her, just for a moment. Just to see what it's like. She can't help herself and she starts to fuck you. The walls come down and she unleashes her true desires. You fuck eachother and your sister cums multiple times. She begs for you to creampie her. You both know this is wrong but there's nothing you want more than to fill your sister with your cum, she's desperate for you. You don't hold back. She is delighted, relishing in the afterglow of her brother's love. Then, a crash of thunder shakes the house. You know what you need to do.