By the end of their first day of incestuous, bloody sex the two siblings had grown more relaxed. She was feeding off of his semen not only during their brutal sessions but also while he rested. His cock was now swollen beyond normal and was nearly the size of her thigh. His glands were producing cum at a rate where he was nearly a constant source for her appetite and he was nearly always ready. She too was gaining strength. She could heal almost instantly and she could store enough of his potency to recover from anything he could do to her. At least so far.
Lying on his chest, they kissed deeply. He thought, "She's so perfect. I want so bad to fuck that tiny pussy, but I doubt my finger would fit."
Almost as if she could read his thoughts, she started stroking his erection with her slimy pussy. He hardened against her and she slammed down on his crotch, crushing on his ready to burst balls. He grunted a breath into her locked kiss as he involuntarily squirted into the air and onto her backside. She giggled at the trick and then laid on him.
"Why haven't you used my pussy? I really ache for you to fill it with your tasty goo."
"Sis, I'm WAY too big to fit in there. Besides, there are so many other things to try first."

She frowned and said, "Even if you tear me open, won't I just heal. Besides, I get stronger each time and somehow I know that if you feed me like that, I will be complete"

His mind swirled with the thought, his body also ached to open her womb. He just wasn't sure she would survive and that thought made him cum. While his little sister gobbled up his orgasm, he wondered...

"What should I do next?"............