On the 13th of every month, the witch demanded the potent power of her sons seeds, because through them she could remain beautiful - forever. She refrained from using any dark magic during the ritual. It was important to her that the semen was given away
Well, it was definitely a little weird and awkward at first but now all I have to do is whip out my dick and my sis is now all about it. Regardless, our parents are happy we're spending a ton more time together and not arguing at all anymore.