Don't blow it you dumb-fuck. Play along.

You slowly raise yourself off of your sister, as you pull yourself out, the tight seal made by your little sister's ass creates a suction that tries to pull your still engorged cock back inside her bowels. You love the sensation it creates but trying to wrack your brain for a way out of this while not letting on that you are completely powerless at the moment is making it hard for you to REALLY enjoy the moment as much as you would otherwise.

"Good, you know now what I'm capable of. Now clean yourself the fuck up, I need to get dad's keys."

Your little sister looks up at you warily as you try to keep calm and start putting your clothes back on.

"You're not going to get away with this, you know that, right?"
"Shut the fuck up, Vanessa, before I make you brush your teeth with my cock that's just been inside your ass."

Vanessa blanches at the thought and holds her tongue. A good thing, because the more the two of you talk, the more likely you'll fuck up and she'll somehow find out that you can't use your powers anymore.

"Mom will know. I won't need to tell her. She'll know something is wrong."
"And what do you think is going to happen? I can stop time. Do you think I'm worried about laws anymore? I can stop time and **** you for days. Nothing can stop me from getting to you. Nothing, and no-one. I own you now. Now shut the fuck up before I prove it to you again. In fact, get the fuck back on your knees. I'm going to make you taste your own ass."

You grip a handful of your sister's hair and roughly pull her back onto her knees, before pulling her face around until it's facing your filthy cock covered in cum and anal juices from your recent plundering of your little sister's bowels.

"Open wide, Vanny. Older brother wants some kissy face."
"No- no. Please don't make me do this. Uly, No! NoooommmMMPPPHHGGHHHH!!!"

You roughly shake your sister's head around using your grip on her hair. Her mouth opens in shock in the sudden pain and you use the opportunity to sink your cock back into your new favorite cock socket, eliciting a disgusted **** scream from your little sister. She starts to flail, but as weak and skinny as you are, you still have six inches and a good fifty pounds on her. You don't have much trouble holding down her tiny frame as you make her eat the mess she made.

"This will teach you, you little slut. I own this mouth. Every time you open your mouth without permission from now on I'm going to stop time and fuck your little face until you learn what it means to respect your older brother. Now shut the fuck up while I use your cock socket."

[Quest progress: Tutorial Quest #2: Vanessa Martinez submission score: 30]

"MMMMGGGH!! COUFF"

Hey, looks like making your little sister taste her own ass definitely helped move the Quest progress bar. That's a silver lining in this otherwise dire predicament you're in. Sure, Vanessa is completely helpless on her knees right now with your balls slapping on her chin while you hump her face-pussy, but you need to somehow extract yourself from this situation, (and her mouth) without her being the wiser, and somehow manage to keep her from blowing the lid on this and getting you arrested.

Wasn't there something you were doing? You got distracted fucking your little sister's ass and then making her clean up the aftermath with her tongue. Right.. you need her help turning her into a sex ****. Though that might be tricky to do right now seeing as you can't use your powers at the moment.