Succubus Sister

It's a full moon and you've decided to stop by your sisters on your way home. You let yourself in as you normally do and find your sister. acting. well. stranger than usual. She is startled by you being there and she seems paranoid, you keep pushing her to let you know what's going on and what the hell is she doing??? She continues to insist you leave, but out of curiosity and concern you stay. She starts acting more and more . strange? And then she starts undressing. you can't understand what is going on but it seems like she's horny? Or is that just in your head. Until all of a sudden . is she seducing you? She is, wait. how does she know about you wanting to see her naked. You're confused, concerned and aroused. Before you know it she's undressing and pulling on your pants, sucking your cock, leading you to the bedroom, masturbating in front of you encouraging you to touch yourself and then begging you to fuck her. Leading to her begging you to fill her full of cum, and then seems to be exhaus. as your dressing and wrapping your head around wtf just happen she sits up horrified and covers herself with a pillow. Wtf is up with your sister tonight?!