he's learning and stimulating your milk. just make sure they air out and doesn't do too too long or your nipples will crack and bleed.

I've heard a "full" completed feeding is 30 minutes on the left breast and 30 minutes on the right. I've also been told by my son's pediatrician that there's no such thing as too much breastfeeding, but there is such thing as too little. Your little one should be fine mama. If you're still worried, the best thing to do would be speak to a pediatrician.