It's okay, I guess.

"I guess it's alright."

Although it makes you a little uncomfortable, you don't think there's any real harm with her fantasizing about you, and it's hard to say no to her with her looking at you so hopefully.

Sarah's face lights up with joy. She jumps up with a girlish squeal and runs over to you to give you a big hug.

"Thanks, Doug! I knew you'd understand!"

Sarah then takes a step a back, and in a single motion, pulls both her skirt and panties down to the ground and steps out of them. You stare at her in shock and confusion while she stands in front of you, her cock pointed toward you. It's not even fully erect and it already looks bigger than yours.

"Um...what are you doing?" you ask her.

"You said you were okay with this." She looks at you eagerly, with a slight look of concern on her face.

It then dawns on you. You thought she was only asking if it was alright for her to fantasize about you, but she was actually asking you to fulfill those fantasies. You stand there awkwardly for a moment, not sure how to respond. She's your sister and what she wants to do is so inappropriate, but you're not sure how to let her down without hurting her feelings. You also feel conflicted and ashamed at your own state of arousal triggered by your sister.

The whole time this moral debate has been going on in your head, however, your eyes haven't left your sister's cock. You are mesmerized by it. Something so large and masculine on such a small, feminine body. Without being fully aware of what you're doing, you have dropped to your knees in front of your sister and reach out you hand toward her cock. Your sister sighs as you wrap your hand around it. It feels wonderful -- so warm and soft. As you start stroking it, it grows bigger and harder in front of you, until it reaches its full size. You can't believe how big it is -- it's almost twice as large as your own.

You little sister's cock is now fully erect and pointed right at your face. A drop of pre-cum appears at the tip and you stick your tongue out to lick it up, causing your sister to shiver when your tongue makes contact. You are surprised by how sweet it tastes. You open your mouth and lean forward, taking the head into your mouth. Your sister sighs again as you swirl your tongue around the head. You lean further forward and take in more of her dick until you feel yourself start to gag. Sarah moans as you start moving back and forth, sucking her in your mouth and stroking her with one of your hands.

Suddenly, Sarah grabs your head and pulls you in toward her, pushing her cock into your throat. Gagging, you try to push back, but your sister is just too strong in her lust and your position is too ****, preventing you from gaining leverage. She starts thrusting in and out of your throat, fucking you harder and harder as her lust builds and you are **** to catch quick breaths when you can. You look up at your sister in panic, but her eyes are closed and her head tilted back as she gives in to her desire. At this moment, you've become nothing more but a hot, wet sex toy for your sister's cock. You know you should feel angry or ashamed, but the fact that your sister is using you for her own sexual satisfaction is incredibly arousing. You don't believe you've ever been harder in your life.

With a loud moan and one last thrust, Sarah pushes all the way inside you and holds you there as you feel her cock twitching. A warm, wet sensation passes down your throat and into your stomach. You can't believe how long your sister's orgasm lasts as she pumps load after load straight into your stomach. You begin to panic as you start to run out of breath. Finally, your sister relaxes, spent, and you're able pull your head back, coughing up some of your sister's cum as her softening dick leaves your mouth.

"Wow! That felt even better than I imagined it would. Thanks, Doug!"

You know you should be angry at how she used you like that, but you can't deny how turned on you feel, kneeling submissively in front of your little sister, your stomach filled with her cum.