A creamy filling.

“Kary, I...definitely love you as more than just a sister,” you begin. “When I saw you walk in the door all fattened up, I knew I had to have you and that I would change however I needed to make you compatible.”

“D’aww, even if growing big titties is a side-effect?”

“Well, not much of a side-effect. What guy doesn’t want big natural tits? I even love that I lactate,” you admit.

“Ohh, so my big brother likes that he is growing big boobies. Will you still play with your fat sister?” Kary feigns resentment.

“I’d love to still play with my fat sister and her fat dick, fat balls, fat tits, fat ass, fat hips, fat thighs and fat belly. Next time we take a break, I’m going to feed you more and make you fatter, so don’t make any new clothes yet.”

Kary spreads your ass and crams her dick against your hole. Her dick is wider than your hips. She pushes hard and...nothing happens.

“Still too small for me,” Kary admits. “But talking about loving me the way I am, and wanting to grow with me, that’s gonna make me blow. I can’t fit my dick, but would you like a creamy filling in your butt?”

“Yes, please!”

“Wow, really? I was just kidding! I can cum in your ass?” Kary asks excitedly.

“If you line up properly, which I can feel you are,” you answer. Immediately you feel something forcing itself into you, and you reflexively relax your muscles, strangely. Then it happens again. You feel Kary’s cum flowing up into you...what a hair trigger! The bloating you feel is a fullness you have never felt before. True to your sister, it doesn’t stop.

“These balls are getting a...rare workout,” Kary observes.

“Not so rare anymore, sis! We are gonna be using those balls a lot more going forward.”

“And you said not to make...any new clothes? You want to see your sister’s...big balls on display, don’t you?”

“I want to see where the cum is made,” you laugh. “Yes, I love staring at your big balls. The rest of you, too!”

“That’s...great! Damn, I’m finished already. How do you feel?” Kary asks as she pulls away.

“I feel stuffed from both ends,” you reply.

“You look comically full. Your belly is resting on the ground. Crap, I overdid it, sorry,” Kary says sheepishly.

“Don’t worry about it! I feel great!”

Kary seems worn out. Hands on her hips, she stands there huffing. Your belly resting on the floor, you drag yourself back around the counter and start a pot of pasta. Kary smiles at you.

“Isn’t feeding me what started this?” she asks.

“It was. Then I drank your cum and then you came up my ass.”

“My curves, bro...you want to see more?” Kary asks huskily.