Your younger sister is brought into the fold

"Thank you, honey." Erin beamed as her youngest entered the room. She sat up straight on your hips and looked particularly alluring as the morning sunlight bounced on her slightly glistening, healthy skin.

You noted the lack of embarrassment on either woman's face. A week ago, Erin would have made sure the door was locked and Dana would have given her incestuous family a wide berth. But here your mother was, sitting on her son's cock, and your sister didn't seem the least bit perturbed by it.

You felt the change in yourself too. As Dana drew close, you couldn't help but begin to feel aroused again. She was young and so fertile. If you were lucky, you could have her waddling around high school a pregnant teen.

Erin smirked knowingly as you hardened inside her. As Dana leaned in to show Erin the photos she'd taken, you notice your sister's eyes move from the screen to meet yours. And in those bright pupils, you recognized your own hunger reflected.

"Happy birthday, Dana," you said softly, sitting up. Erin squirmed as you wrapped an arm around her waist and held her against your body. "This is such a big day."

"How so?" Dana smiled.

"We don't have to keep it in the bedrooms anymore. At least not for a while," you chuckled darkly. Erin blushed and pinched your shoulder, but looked pleased nonetheless.

"Come here," you commanded your sister. She shivered, and then crawled onto the bed. You eyed her breasts as they wobbled in her shirt. She wasn't wearing a bra.

You palm her cheek and admire her face. Like every other female in the family, her eyes gleamed as they started into yours. With love and desire.

"What's going through your head?" You asked her. "Nervous?"

"No." She shook her head. "A... dream I had. You were there with me. And others."

"We all have those. What did you see?" Erin urged warmly.

"You were different," Dana whispered, biting her lip. She squirmed stop your thigh. "Just using me for your pleasure. Filling me again and again until I was swollen.

"I woke up feeling so hollow," she moaned, grabbing your hand and pulling it up and onto her chest. "Upset with myself. For not being pregnant like Mom or Caitlin."

You lean in. You peck her on her lips first before deeping the kiss, sucking on her plump lips.

"That's not something to be worried about, Dana." You murmured softly against her ear.

She yelped as you pushed her by the shoulder and onto her back on the bed. Erin bit her lip and smiled as she rose up off of you and crawled above her daughter.

"Right now?" Dana asked softly. Not with fear, but with clear excitement.

"You'll never not be pregnant," Erin laughed musically, lifting Dana's head and restiyng it on her lap. "You're going to be nice and swollen by the end of senior year, baby."

"Oh God." Dana moaned as you wiggled between her legs. Your mother deftly undid the buttons on her daughter's blouse, and it fell open to reveal large, pillowy breasts.

With a yank you had her shorts off, exposing a perfectly pink, slick pussy. Dana shivered as you crawled stop her and maneuvered your cock between her thighs.

"Your brother is really big, sweetie," Erin soothed. "This will hurt a little. Here."

She lowered her torso a little and pressed a teat against her daughter's lips.