When are you planning on telling your lo about sex? And how are you going to do it?

My 6 year old niece started asking her parents where babies come from and how they get out of the belly when I got pregnant. They still haven't told her. In fact my bil told her that he and her mom pricked their fingers and mixed together their blood, added some coke, and bam, she was there. No joke.

My plan is to tell lo when she starts asking about it. I'll probably use some sort of book to help.