Twilight Sparkle and Rainbow Dash have reached the next step in their relationship. They're ready to have a foal together. Rainbow has volunteered to get pregnant, and a sperm bank has provided a magical egg full of prime stallion semen. So all that's left is for Twilight to get it inside of Rainbow. Well, that and eleven months of a now-pregnant Rainbow Dash growing increasingly cranky before the baby finally arrives.

The first part of this story was written for (and published with) the Jingleclop exchange, but that story/collection seems to have vanished from the site. Here is the full version, with all the original impregnantion sexy times, and also plenty of sweet fluff added on.