Make you beg

You couldn't take her teasing any longer, you needed to have her babies. You threw your legs open and stared at her in abject desperation.

"Breed me!" You whimpered meekly.

"Not good enough," you sister said and started to pull out, but you wrapped your legs and tail around her to lock her in place inside of you.

" Wakinya, please!" You nearly screamed, "I need this! I need this more than anything! I need to have your babies! Please!"

"Keep going," your sister grinned as she thrust deeper.

"You're the sexiest, most gorgeous monster who ever lived," you said, and you weren't just stroking her ego, "You deserve only the second most gorgeous to be the mother of your children."

"Well then I better go find her," your sister teased.

"NO!" you screamed, "Put a baby in me! PLEASE! I'll do anything you desire. I'll be your your whore, your cocksleeve, your live in sex toy do you and our children! Just breed me!"

"That's what I wanted to hear!" She hissed as she rammed her enormous bitch breaking cock into your womb. You came immediately and didn't stop the entire time your sister fucked you. Your combined pleasure caused it to literally rain fresh hot cum all over the landscape and you.

You were powerless under your sister's onslaught, helpless and pathetic in your pure orgasmic bliss. A monster of your power should never submit to another, but your sister was the exception. A futa as gorgeous and sexy and powerful as her deserved to do whatever she wanted with you.

Your legs finally went limp and you could only lay back as she had her way with you. The slapping of her enormous balls against your ass sounded like thunder. As impossibly tight as your pussy was, her cock felt like the biggest thing in the world. She didn't fit inside you in the least, which meant she fit perfectly.

The downpour of cum from the sky mixed with the geyser of cum from your painfully hard, mountainous cock, drenching the both of you. As stunning as she was already, your sister looked like a goddess with her face covered in slimy hot ejaculate.

As it pooled across the land, lesser monsters excitedly jumped in to frolic with each other, and a loosely connected orgy started in the meadow. Some fawns jumped into the arms of a chimera and made out passionately in the cum rain. Elsewhere a naga wrestled for dominance with a lioness and were covered in cummy mud.

Finally you sister grabbed your hips in her talons and jackhammered your pussy so hard it caused a small earthquake. You screamed with joy as your tits and cock rocked back and forth. Then, after so long, you got your wish. You felt your sisters thick, hot seed fill you up. You released one final tidal wave of cum, the rain picked up until you barely see your sister on top of you, and lightning struck everywhere around you. When she finally stopped filling you up, you looked nine months pregnant with octuplets. With any luck, you really were pregnant too. Your sister grunted as the last spurt of her seed splattered your face, and you collapsed together in the mud, wrapped happily in each other's wings.