Please help me with books / websites / other amazing recs

We’re having #3 this summer and my oldest is 6, so old enough to really have a lot of questions about the process. I don’t want to freak her out but want to be appropriately truthful. So far I am pretty much dancing around it and she isn’t pushing it but I’d like to do better. The questions seem to be coming up more as we get closer and the kids spend a lot of time playing “baby in my tummy” and “let’s go to the hospital to get the baby out”. My 3yo son told my husband at bedtime that one stuffed animal was pooping out his baby (I’m not really worried about the 3yo understanding - just thought that was funny!)