Looking for feedback

I'm currently working on part 3 of Sisters' Pleasure Brother's Pain, but I have reached a place where I don't want the girls to finish off Billy's privates because then they don't have them to play with. But I am thinking that with this series I will eventually want to make it so that the sisters can just magically restore Billy's privates as many times as they want so that things can get extreme. I'm leaning towards just leaping forward and making it so that the girls can destroy Billy's privates and bring them back, so that Jill can eat her brother's privates for breakfast on her 18th birthday. But I would love to hear what you think, do you like my idea of giving the sisters the power to bring back destroyed privates so that they can destroy them again and again, or does this level of fantasy ruin the genre for you? Thanks.