GOOD ENDING

Just when Big Mac was preparing himself to have this attempt fail and to accept his inevitable demise, Flutterbat stopped sucking him dry. She released his cock from her mouth, her expression shocked and scared. When she raised her eyes to his, the earth pony knew that she was back to herself, at least mentally. Fluttershy got up, staring at him with disbelief, her latest actions fresh in her memories. Without making a sound she flew away, without even watching her back, leaving a breathless yet alive Big Mac behind. He watched her go, before he fell asleep.

Almost three weeks had passed since that night. The day after Big Mac told his sister about Fluttershy mutation and what she had tried to do to him (No point trying to hide it from the element of Honesty, and he wasn’t that good at lying). After that she got Twilight to use her skills of magic to understand the reasons of Flutterbat return and how to cure it once for all. And even then alicorn princess told her to pass by her twice each weeks just to make sure everything was going fine. For the rest, they kept this whole ordeal of the rapist Flutterbat between the Mane 6 and the Apple Family. Last thing they wanted was to let this fact spread, ruining Fluttershy reputation.
In those two and a half weeks Fluttershy kept a low profile, doing her best into avoiding him those time they meet when out to buy stuff at the market. It was no surprise for the farmer. He knew how shy and sensible her nature were. After having him almost raped, she had to feel pretty miserable, he thought, while shaking some tree to make apples fall. He was just thinking to go visit her, ensuring her that there was nothing to worry about. And then he heard a voice calling him.
“Big Mac”.
The farmer knew that meek and sweet voice. He turned around, seeing Fluttershy standing close to a tree with her usual clothing. Now that summer was nearing to an end she had the chance to go back using her most covering outfits. “Fluttershy” said the earth pony, smiling. But, despite his best attempt, the shy pegasus covered herself behind a tree. “Don’t you worry, Fluttershy, I’m not mad at you” he assured, “And neither is my sister, if I can guess what you’re thinking”.
“Even after what I did to you?” she asked, “I doubt it”.
“It wasn’t really you”.
"Yes, it was".
Big Mac looked at her, confused, "What do you mean?".
"I mean that I did what I did because... I love you". The earth pony was speechless, so the shy pegasus continued, "I always had a crush on you since when we met when we were foals but I was too much shy to admit it and so I've kept it from myself" she was blushing madly. "And when I saw you last night, under my savage state, my feelings for you plus the thirst I had, made me do what you and the others know".
"Fluttershy" muttered Big Mac, trying to find something to say, "I... well".
"Don't say a thing, Big Mac, I already know. I have issues".
Those words made the earth pony snap from his stuttering. "Listen, Fluttershy, we can't change what happened that night, but that doesn't have to change what you are" he said, "You are a great friend, more brave than you think you are, with amazings skills with taking care to a lot of animals. Do not let your sins spell what you are".
"Big Mac" it was Fluttershy turn to look impressed, "You... you are truly the best pony" she said, admired.
"Nah, I'm just an humble farmer that doesn't want to leave a friend in need". The two smiled at each other kindly.
"Thank you for your words, Big Mac. Maybe I could repay you by offering you a dinner".
"Would love to".

And whatever resulted from such dinner, the two remained didn't had to worry anymore of the return of the Flutterbat.

Author's Note

My first work for the adult pages. I feel like, while far from perfect, is still a good start that will possibly make other writers try this type of story.
I had opened a new group focused on that kind of works called Boobs Over Muscle that I've made months ago (And hopefully, once I learn how to do it I will post it there).
Will I do another one? Who knows.
Edit: Ok, so I've tried to fix all those mistakes and I have even changed the ending, so that people can be free to decide if the two will get together or not.