The Empress’s New … Rod (Futanari Erotica Fairy Tales Book 15) by Julie Law

Empress Isolde had almost everything a woman might want. She had vast riches, few were as powerful as she, or as beautiful. Her people worshiped her. She didn't have anyone to love, not truly, but she didn't particularly care either, though she desired a child as she hadn't desired anything before.

She was unable to conceive though.

Her kingdom was filled with magic and those that used it, and so the empress had a bright idea: she would grant riches and power to the one that found a way for her to have a child. Unfortunately for her, the only one who proved to have even the slightest hint of an idea of how to do it was the clumsiest witch in the entire realm.