I've got an almost 5 month old and a just turned 3 year old. Recently the 3 year old asked me if she could have some of 'Jack's milk'. I weaned her at 8 months - so I know she wouldn't remember.
She had recently asked to try some of his formula milk, which I let her and she did not like it. So I reminded her what the milk in Jack's bottles tasted like and she pulled a face and decided she didn't want to start breast feeding again. So now when I'm breast feeding Jack, Caitlin just sits on the other chair with her 'baby' and feeds the baby while I feed Jack.
I agree that it is an attention thing, but she seems more happy playing the mummy role than the baby role, so I'm happy to let her pretend to breast feed her child.
However, I did have to laugh the other week when I asked her what she wanted for her birthday. She replied "Boobs" so she could feed her baby like mummy feeds Jack.
Rere, NZ, mum of three