I break it.

We had a hard time taking Nate off the bottle. He drank juice and water from sippy cups just fine, but milk had to be from a bottle. Eventually, we just put all the bottles away and let him deal with it. By then, he was eating enough to not need the milk anymore. About a week or so after we put the bottles away, he drank milk from sippy cups.

Then he started getting his 2 year molars, and he got attached to one special cup for milk.

from Amazon

The Nuk Learner cup - with handles. He didn't eat as much when he was teething. The spout of this cup is soft like a bottle nipple, but it's shaped like a sippy cup. He liked chewing on it. When his teeth were hurting and he was hungry, he wanted his special milk cup.

And one day he stopped drinking milk out of anything besides that cup. We bought a spare spout because his teething efforts were wearing out the original. I threw away the original spout in November. We started trying to get him to drink milk out of other cups, but he would not.

The week before Christmas, not long after we opened our Christmas gifts, he broke the replacement spout. He has not drank milk since.

It's a bit inconvenient because when he got fussy before, a cup of milk in his milk cup settled him down like nothing else. On the other hand, it's good because he has not been constipated since he stopped drinking milk.

It is sad, though. He will occasionally ask for milk, then remember and say, "Where's your cup? I break it."