My Fake Baby Does Anyone Know How Those Fake Baby Dolls They Use In Parenting Classes Work?

Does anyone know how those fake baby dolls they use in parenting classes work? - my fake baby

In my school, I saw a few girls around with fake wrist for a project. But I do not understand, can not simply remove the batteries or something? And as the teacher knows that the baby does not sit in the room, "Mom," is to be with her during the whole time? So, how is what I think and change the baby (as her buttocks)?

Please someone tell me that!