Maddison knows & actually I heard her explaining how it got in & how it was gonna get out... To one of her school mates once! Then also told the teacher all about it. When I was first preg I bought maddison the where did I come from book... She was 6 & is extremely mature for her age... She read the book with me, then read it by herself & told me.. "I know babies get there by Daddies wriggiling ther penis, until it feels nice for both of them.. inside Mummies vagina"... That was it...
She saw me when I was in labour at the beginning of the day & later that afternoon, before doing off to hospital, she knew it had to come out of my vagina & she always winced when she'd think about it!!!

My nephew on the other hand was 7-8 yrs old & truly disgusted when he saw the Where Did I come from book & burst into tears telling his Mum (who had borrowed it to read to him) that it was sick!!!

I dont know if that will help or not, but I found it to be really easy...