My 11 month old boy REFUSES to drink anything other than formula! It doesnt matter what kind of baby juices i offfer him, he spits it all back out! he wont even drink water. We've tried several sippy cups, smalll bottle, even out of plastic cups, nada. He recently had a tummy bug and I was worried about dehydration! Anybody have any tips on how I can convince him that liquid is his friend??