You enter for your reward

Emily's breasts are the most perfect thing you could have imagined. The image of two petite, perfectly symmetrical breasts etch themselves into your memory, perfectly complimenting her petite frame. And crowning these two magnificent globes are the most perfect dark nipples. Your sister is as good as naked in front of you, the only thing covering her most vunerable area is her panties, with a clear wet spot on them. She is wearing nothing but her panties, her panties and her necklace. And its open for you, and the key to your cage is visible, teasing what's to come.

You cannot stop staring. And Emily notices. "Do you like what you see?" she says in a seductive, teasing tone.
"Y.. yes mistress." is all you can muster. She smiles as she leads you into the bathroom. You want to do nothing more than to suck those perfect breasts, take them into your mouth and savor every second of her. Your cock strains against the cage by the mere thought of it. But you know you are not allowed to. You know she holds all the power over you, her with that damned key. That key hanging between her two perfect breasts.

Emily wordlessly takes command of the situation, pulls your skirt up and tells you to hold on to it, revealing your panties, which she slowly pulls down. Your pink cage is revealed to her, and she takes her sweet time caressing it, being much more hands-on this time, her soft fingers caressing your sensitive balls. You try to hold back a moan, try to be a good obedient boy to her but the sensation is too much, as a soft groan escapes your lips. Emily smiles and looks up at you.
"Does my little toy need to cum?" You nod helplessly as she chuckles.

"Let's see what we can do." she says, putting the key into the lock as it effortlessly snaps open. She removes the cage, as you can feel your cock swell as it gets space to grow. Emily gently puts one of her fingers on your base, and slowly trails it all along your length, to your leaking tip. The sensation is overwhelming. You moan once again, loud this time.

"Now I want you to be a good boy and last longer than you did last time." she says. "That shouldn't be too much to ask, should it?" You wanna be good for your sister. You wanna make her proud. But she doesn't make it easy. She gets on her knees and pushes her tits together for you, opens her mouth and lets her tongue hang out. There is no way that you are going to last for any amount of time looking at her like this. But are determined to do your best. You get ready to strip as your sister stops you. "Keep the skirt on." she commands.

This leaves you having to hold the skirt with one hand as you stroke your cock with the other, all while looking at your topless sister. As soon as your hand meets your cock your entire body tingles. This is going to be hard, but you are determined to last longer than last time. Not that it should be much of a challenge. As you stroke, you do your utmost to hold back your climax, but your eyes can't leave your sister kneeling in front of you, presenting her nubile body to you.

Then after just a minute or two she says it. "Cum on me John. Cum on your sisters tits."

It is enough to bring you over the edge. After just a few minutes, you shoot your load all over your little sister.