Tries to convince you

Lust clouding not only her eyes, but her judgement too, Shelly climbs on top of you, rubbing her wet snatch along your length, causing you to groan, but you place your hands on her shoulders. "Shell..." You say softly, "I don't know if I'm ready for that yet..." She looks at you longingly, but also thoughtfully. Slowly, she lowers her face down towards yours, causing you to blush furiously, but she doesn't go for your lips. Instead she moves her face to your neck, kissing and biting along it. You let out a small whimper, unused to this treatment. "H-hey!" You stutter, "C-cut it out! If you l-leave a mark Mum might see!" Your sister ignores you as she suddenly begins to suck hard on the base of your neck. You bite your lower lip, but don't stop her. After 10 seconds or so she pulls away and licks the same spot. It's sensitive. You gulp as you realise what she's done. "Shell," You begin, "You just gave me a hic-" You are cut off when she places a finger on your lips.

A pair of hands snake their way under your shirt, feeling slowly up your chest, until you feel your older sister lift herself up slightly and pull your shirt over your head. She kisses up your chest, along your neck and hickey and to your lips.

She lightly kisses you, just under your lips, and begins to rub against your cock once more. "Pleeeaaase John," She pleads, a primal need in her voice, "I need your fat cock in me, I neeed it," She begins to rub harder, and you feel her juices slowly run down your length. You bite your bottom lip.