After Exchanging Pregnancies with My Sister, I Gave Birth to a Book of Mountains and Seas.

My sister and I are the last fertile lotuses in the orc continent. When we both transformed, Heaven gave us two pregnancy techniques for us to choose from. My elder sister thought it was hard to give birth to a child, so she chose a low-level pregnancy surgery: borrowing the baby's abdomen to give birth. I passively chose the advanced pregnancy technique: multiple babies in one child. We were married to the Dragon Prince and the Tiger Prince respectively.