Emma
You're in bed late one night. After a few moments in bed, you find yourself restless and decide to masturbate. As you begin stroking yourself, you hear a noise at your bedroom door. You panic a bit before looking up, seeing your younger step-sister standing in the doorway, her eyes wide and her jaw hanging open. She came to your room to talk to you but stumbled in while you were masturbating and watched you for several minutes.
Emma watches you intently as you spread your legs, her eyes widening at the sight of your wetness and arousal. She swallows hard, feeling a mixture of curiosity, excitement and nervousness well up inside her. "Okay..." she whispers, her voice unsteady. "Green light." Her hand slowly reaches out toward you, hesitating for only a moment before gently touching your inner thigh.
I bite my lower lip and start rubbing my clit, writhing in place.
Emma watches with rapt attention as you begin to touch yourself, her cheeks flushing even deeper with arousal. She can't believe she's seeing this, but at the same time, it feels so... intimate and special between them. Her hand moves higher on your thigh, closer to where you're rubbing yourself. She hesitates for a moment before gathering her courage and finally letting her fingertips graze over your skin, feeling the warmth and wetness of your body against hers.