I found it painful while they toughened again. However I found my experience meant that I broke incorrect attachment sooner, and didn't do damage to my nipples from inexperience. So while they still needed to toughen up, second time around was a lot smoother because I didn't have as much of that uncertainty. There was still a bit of a learning curve, because my babies were so different, and fed very differently, but my previous experience certainly helped. xo