I have found with those tt cups the straw is too short, Caleb goes to put his mouth over it and ends up biting the lid instead, he likes a big straw so we got him one with a big straw, he still has to bite the straw to get the water to come through and then suck it up though, he likes to bite the straw. Im trying to only offer him these kinds of cups instead of the old ones where he had to tip it up and bite on the big thick teat to make the holes open, we are getting alot of positive response to water, drank about 6 oz yesterday in total but no such luck with the milk, i offer it and he pushes it away, i offer again and same thing, i then offer him water (from anotehr cup) and he drinks it!