My 18 month old son is on the bottle, I am trying to get him off of it, but I have a 6 month old daughter, she needs them, so he sees them and still wants them. Also, he will not drink milk out of anything but a bottle. I have tried everything. Cups with straws, regualr sippies, the ones with the sylicone tops too, nothing is working, any ideas? *Reminder* I can not get rid of the bottle, I have a 6 month old daughter.