What a silly question! Of course they said yes. After explaining the situation to Twilight, she begrudgingly agreed to cultivate and supply the F.A.S.T potion on the condition that Rainbow only used it on her new girlfriends, though decided to rename it the Fertilization Under Toxic Affection potion, or F.U.T.A for short. It was only after a while that Rainbow, Applebloom, Sweetie Belle and Scootaloo saw the effects of the "fertilization" side of the potion, as every member of the CMC had gained large rounded stomachs that could only develop from carrying a growing foal, they were all pregnant. Pinkie Pie was ecstatic to learn she'd have to throw a foal shower for the three of them, though others were more concerned that they were all the youngest mothers Equestria had ever seen, not to mention that the father was none other than Rainbow Dash, a mare who always found herself in dangerous situations and was a fair bit older than the CMC, one of whom was her adopted sister!

There were mixed feelings all around that's for certain, the only ones who were 100% happy with the situation was Rainbow and her girls, Rainbow got to pass on her awesome genetics and the CMC just enjoyed expressing their love for Rainbow Dash, if that meant squeezing as many foals out of their cunts as possible then so be it! Luckily, Rainbow decided that three foals was enough and decided to wear protection in future or simply switch from constantly fucking them right in the pussy to constantly gaping their assholes with her cock, not to mention fucking their faces until their jaws ached. Whatever it was that the future held, they were prepared to face it all......... and still make time to fuck as often as possible.

The End

Author's Note

Thank you superfun for this story idea! I hope you enjoyed it :)