How can I stuff my rag doll so she looks like a mama?

Please forgive me, but your question made me laugh out loud! Just wasn't what I was expecting to see here. :-) Anyway, I'd imagine you could make a cotton ball-sized ball of rags, sew them to the doll's chest, then cover the balls with a piece of fabric that you hand-sew in place, gathering and folding as necessary to maintain the rounded shape.

I've never even consider this one. I'm thinking you could use small "bean bags" like the ones used in corn hole, maybe smaller - depending on your doll size.

Cotton balls, fiberfill stuffing, quilt batting. My choice would be fiberfill or quilt batting as those can easily be washed. If using cotton balls, after a run through the washing machine, or even hand washing, they will become lumpy and misshapen. No mama needs to have lumpy breasts!

tie strips of rags into knot(however large you need/want the breasts to be) cut off excess material around the knot sew loose ends under while attaching knot to chest of dollies. some more ways to do it https://textilecreationsuk.blogspot.com/2013/02/which-breast-is-best.html