[This was a custom request] Your sister is lying on her bed, about to enjoy some private time masturbating when she's interrupted because she hears someone at her door. She calls in in, covering her modesty - somehow she knew it was you. She's just in her underwear but she doesn't seem to mind. She tells you she's noticed you watching her before... in fact, she's noticed a lot of things that you've been doing. You're pretty terrified by exactly what she might mean by this but your horror turns to sheer arousal as she tells you she knows how much you want to see her naked, and begins to flash her tits and pussy straight in your direction. Your own sister starts to masturbate in front of you while she reveals all of the stories that she's know about you all along... She knows you've watched her naked or masturbating multiple times, she knows you've been feeding her your cum on her toothbrush or in her morning cups of tea. As she reveals all of your most embarrassing secrets, she starts to play with herself more and more intensely. She pulls out a dildo and starts sliding it up and down her slit while revealing she knows your dirtiest secret of all... the one night when you thought she was snoozing and you took it to a complete other level - pressing your cock against her tight slit as you wanked yourself to orgasm. She knew all along... and the idea of you cumming inside her excited her so much that she's masturbated over the thought ever since. She ploughs herself with her dildo while you watch until she cums hard around it - talking about her own brother's cum inside her. When she's finished, she opens her legs and invites you to fuck her for real this time. Really cum inside her... deep inside, hitting her womb with your brotherly seed. How can you say no?