Immediately go to see Annie

Jill rose wiping Arthur's cum off her chin with the back of her hand. She smiled at her brother in law, and he ran his hand through her hair, enamored with her.

"Know what we should do?" Jill smiled. Now was when she'd make her judgmental brother-in-law and sister pay.

Arthur gave her a concerned look.

"We should go tell Annie" Jill said as Arthur's eyes shot open and his head began to shake.

"No... we can never tell...." But as he objected, whispering loudly, Jill had already headed off down the hallway, nude, covered in her brother-in-law's cum, toward her sister's bedroom.

Arthur followed several paces behind.

Jill cracked open the door to her sister's bedroom. The air inside was warm and Jill felt it on her wet pussy and cum-covered breasts. Annie did always like to sleep in a warm cozy room.

From her current perspective, her sister laid in bed, turned away from the door. Jill could only see her back, but there was the perfect opportunity to sneak into bed behind her, in Arthur's empty spot.

She squeezed through the door quickly, before Arthur caught up with her and gently climbed into bed, her anxiety building, lying naked next to her sister. Despite being a proud slut, this would still be new for her. And she had no idea just how much Annie would resist.

She heard Arthur enter the room behind her, not making a sound. It was too late for him to say anything. She was already shuffling up behind Annie, spooning her in bed.

Annie stirred, letting out a pleasant moan. Jill brushed her sister's curly black hair aside and kissed the back of her neck.

"Mmmm honey..." Annie whispered, somewhere between sleep and waking. And Jill was immediately turned on by the prospect of seeing her sister's most intimate behavior.

Jill wrapped her arms around Annie, one hand reaching under her night t-shirt and cupping an ample breast. The other slowly tiptoeing down Annie's abdomen, down into the pair of boxers she was wearing, past what felt like a thick, curly bush and cupping her pussy.

Jill glanced up at Arthur's face, covered in terror.

"Oh Art," Annie said as she began to writhe under the sheets. Jill's pussy throbbed, moist, ready to go. "Do you want me right now?" Annie asked in a whisper.

And though Jill couldn't answer, she kissed her sister's neck again, several times, working her way up to a spot behind her ear, tickling it with her tongue.

Things were working perfectly. She'd teach her sister and brother-in-law about the joys of sex, slutiness, and kink. She'd pull them right out of their vanilla sex lives.

Or so Jill thought, until she heard the next thing her sister said. A suggestion so surprising, so impossible from the mouth of Annie, it blanked Jill's mind and made her freeze in total shock.

"Yes, Art honey..." Annie whispered. "Do you want to..."