What to tell my 4 year old..

Just Me • Have a 4 year old daughter and a Newborn GLOW baby girl born 22/04/15..so in love 💕
My 4 year old is asking how baby is going to come out from my tummy and how she got out also. 
I really don't know what to tell her and ive been just laughing it of but now the time is coming closer (2-3 weeks to go till induction) she is asking more and more. 
What have you told your other children about how baby is gonna get out?