I guess you don’t know how they will react you just have to know you tried your best to prepare! I think the tandem feeding could help ease the jealously of having a new baby.
Our story is:
DS1 was 2.5 when DD born. I had been working FT so he was really just feeding am & pm. Sometimes not at all if I worked early or late.
My attitude was… if he stops when I am pregnant that is great as I don’t have to bother weaning. If he is still BF when baby is born that means there is plenty of milk and all the stress and tears regarding feeding I endured as a first time mum wont be repeated. Great.
What happened was my milk went down significantly when pregnant and was possibly mostly gone as couldn’t get any by hand when I tried. So I think he was just doing it for comfort. However just as I thought yippee he has stopped the colostrum came in and he loved it. So I went with the flow and when DD was born she had milk on tap. She put on weight and lost none. Win win. In the mornings by feeding he helped with the fast let down,
Feeding DS1 at night was ok as it was at a different time to when the baby needed feeding or we would tandem. In the mornings it was too much like hard work to feed both. 3 months in I decided I needed a plan to stop. It took about three months. I began limiting time in the mornings by counting to 30 in my head then 10 out loud to him (and then gradually shortening the counting in my head) I then spent 3 months of talking to him almost daily about when he was 3 he wouldn’t be getting milk anymore.. along with the promise of a space rocket (I don’t employ bribes often!!) and on his third birthday it all went very smoothly!
With regard to preparation – it helped that he was 2+when I began talking to him about it and that I worked so no day feeds and he very rarely fed at weekends during the day.
The book I read to him had photos and text about breastfeeding and I just stressed those talking points “baby can only have milk, you are a big boy you can have milk and x/y/z” “its sad mummy cant play ball with you but I can read a book with you” and found photos of babies feeding and tandem to normalise everything for him. I didn’t encourage or discourage bf or tandem feeding, just let him find his place. I didn’t feed tandem as in both at once often more because he wasn’t as interested but if he asked I would accommodate and it soon became a bit boring for him. It was handy after bath though when I would feed both in my bed and read stories in the earl newborn days,.
Book was called Let's Talk About: My New Baby
by Stella Gurney (Author), Fiona Freund (Author)
I also found the siblings part on this helpful for the general new baby theme– I took some of the points on bored: lucysymons.squarespace.com/top-tips/
Good luck!