The best way to get your body to make ANY milk is to put to the breast often. There are also supplements/prescription meds you can take to increase your supply or help relactate.
I did mixed feeding last time. I didn't do both from the get go (I established bfdg 1st) and my baby was not confused and fed well with both. So a sweeping statement like: "you need to do both from the start or it won't work" is not true.
Some babies do get nipple confusion, because sucking and suckling are very different. Bottlefeeding can mess up bfdg, it can hinder your milk production and make it very hard for your baby to latch correctly (which is HE!! on your nipples, believe you me). That is why I established bfdg first when I did it.
It is possible - the trick is to latch the baby on often and perservere - remember he is already accustomed to bottles, which is a very different way of feeding. If he's HUNGRY, he might get frustrated at your breast because he wants to feed in a way that is easy and familiar. If that happens, I would try giving a half feed of formula and THEN encouraging to latch. A good pump would also help... if you can get your body to produce a little milk you can hand express some and put it on your nipple to give him the idea.
The Latch is the Holy Grail of bfdg... get that right and you are 3/4 of the way there. Baby needs to take lots of boob into his mouth in order to get the milk flowing well, to make sure he gets enough and gets to the hind milk and to stimulate your body to start making more. Tummy to tummy, back in a straight line, top lip up and bottom lip down. Watch for swallowing. Look at pictures and videos of it, and get hands on help and support from a mw or hv. If you have a local bfdg group, GO.
HTH
