Breastmilk in a sippy cup? Any success mamas?

[Liaklong]

My son is 12M and I'm hoping to breastfeed him until he is at least 18M. I'm heading back to nursing school full-time after that, so I'll see how it goes. I pump very infrequently now, but when I need to for class I don't want to put it in a bottle (he wouldn't take it from a bottle anyway). I've been trying sippy cups w/my milk, but he's not having it. He'll drink water from a sippy, but not breastmilk. This makes it hard when my dh needs to put him to sleep when I'm at school late. Anyone have success w/this? Any specific kind of sippy you liked best?

Thanks