How did you explain breastfeeding to your older kids?

Br

My oldest son is turning 5 on Sunday, and my youngest is due on Saturday. I also have a stepdaughter who will be 7 in December. My stepdaughter wasn't breastfed, and neither was her mom's other child. My son was, but it's been so long that I know he doesn't remember. I would like to breastfeed again, and I'm looking for kid friendly ways to explain what mommy is doing. Thanks, guys! ❤️