I am successful about 40-50% of the time. Often, DD burps on her own when I change her position. I also use the Dr. Brown's bottles. I breastfed DD1 and I was also only successful getting an audible burp out of her about half the time. It seems the more efficiently and calmly DD feeds, the less likely I am to get a burp, which I have always interpretted to be a good thing.