Well...neither of mine were biological, so no breastfeeding here. And Little Man didn't come to live with me until he was 17 months old. Pretty sure he was taken straight off formula and put right onto junk food :(. I have tried a lot of sippy cups. Probably spent hundreds of dollars on them until I found these guys right here (https://www.amazon.com/Munchkin-Miracle-Trainer-Green-Ounce/dp/B00MRZIFD0/ref=sr_1_3_a_it?ie=UTF8&qid=1532830774&sr=8-3&keywords=360+sippy+cup). I'm sorry, I've forgotten how to do the cool link thing like I used to be able to do. Anyway, these have been teaching my daughter how to drink from a real cup, and both kids enjoy drinking from them. I wasn't sure how they worked, so I had to try it out for myself when we first got them! We have a ton of them now. Love them!