Family Ties/Go in and give Heather what she wants.
Instead of taking a risk with your mom, you decide on the easy route and give Heather what she wants. Moving silently, you sneaked into her room and quietly closed the door, locking it to ensure that you two won't be interrupted.
Your sister hasn't noticed you in her room yet and instead was fully focused on pleasuring herself, large D-cupped tits bouncing as she brought herself to another climax. Not wanting to interrupt her fun yet, you decide on simply taking out your cock and began to rub it, slowly to avoid being noticed.
"Oh god Timmy," She said and came once more, laying exhausted on her bed but then she heard the sounds of you rubbing your dick and turned toward you.
Her eyes widen and she stood up in alarm, standing across from you. "Shit! T-Timmy, were you there the whole time!?" She forced herself into a loud whisper, using the blankets to cover herself. It was an odd sight you think.
A naked 16 year old bombshell of a girl and her 9 year old year brother, both buck naked.
"Yup and I heard how you were moaning my name," You smile and it doesn't escape your notice on how her eyes drifted to your dick. You swallow the lump in your throat and continued. "I can tell that you weren't enough with that toy though. How would you like the real thing?"
She did nothing for a moment and you think that you might have made a mistake when she dropped the blankets.
Your jaw drops as your eyes took in her naked form. Large D-cupped with her nipples erect, either from the cold or being horny, and her pussy still wet from her previous actions. Her skin was flawless with long blond hair like mom's and green eyes that were filled with lust.
She put every porn star you ever watched to shame, made them look normal compared to her.
Heather slowly started walking toward you, hips swaying seductively and breasts slightly bouncing. "The toys are never enough. No matter how many times I came, I could never feel satisfied. So yes Timmy,"
Coming to stop just before you, Heather went down on her knees so she could meet your eyes at an even level. Your bright blue eyes met Heather's green ones as her face drew closer.
"I would love the real thing.
With that, the two of you kissed, tongues eagerly dancing in each other's mouths. It started off as innocent and quickly began lewd as you two swap spit like rutting animals, moaning all the way. Both of your hands explored her body, groping her chest and fingering her pussy while Heather's own found themselves around your dick, jacking it off.
Suddenly Heather leaned forward and the action made you fall backwards onto the floor. Thankfully her floor has carpet so the impact doesn't hurt but even if it didn't, Heather's tongue in your mouth would have made you ignore the pain all the same.
Finally you two broke apart, panting for air. She sat on your hips, what little moonlight coming in her room highlighting her form that made her look like a goddess
"I'm going to fuck you Timmy," She said, her hand moving your dick to her neither lips, rubbing your shaft against her clit that sent shivers of pleasure down your spine. "We're going to fuck until the sun's up. You want that Timmy? You wanna have fun with your big sister's pussy all the way to dawn?"
The offer is extremely tempting but then you remember the trip in the morning. If the two of you fucked for so long, your family might notice something. Perhaps one good fuck and offer to have more fun on the trip.